EurOMA 2010, Porto, Portugal , http://www.euroma2010.org/
Conceptual model for assessing cost of security in global supply chains Juha Hintsa (
[email protected]) Cross-border Research Association, CBRA, Lausanne, Switzerland Toni Männistö Cross-border Research Association, CBRA, Lausanne, Switzerland Juha Ahokas Aalto University School of Science and Technology, Helsinki, Finland Kabi Zaghbour Solvay Brussels School of Economics and Management, Brussels, Belgium Ari-Pekka Hameri University of Lausanne, HEC, Switzerland Jan Holmström Aalto University School of Science and Technology, Helsinki, Finland
Abstract After the 2001 terrorist attacks, an avalanche of new initiatives to secure global supply chains have emerged. Government pushed SCS initiatives are sometimes perceived as costly by the private sector, thus calling for SCS cost modeling research. In the literature references with cost factors and values touching various aspects of cost of SCS are discussed, but no holistic model exists today. This paper aims to fill in this gap by first developing a three category SCS cost conceptual model, and then testing the model with a real life case company and supply chain. Keywords: Supply chain security, Cost management, Cost of security
Introduction Before year 2001, designing, implementing and promoting various security measures in global supply chains while fighting against theft, smuggling, and other types of crime, was a diverse function of various supply chain operators, cargo owners and governmental agencies – each looking at crime risks and cost effective security measures from their individual perspectives. The ”9/11” terrorist attacks changed this paradigm towards government pushed supply chain security (SCS) programs, regulations, standards and security measures, through initiatives such as C-TPAT, CSI, 24 hour rule, ISPS, EU AEO, and many others (see e.g. Donner and Kruk 2009 for introduction to a large number of post-2001 SCS initiatives). 1
Ever since the end of year 2001, the cost of enhancing security in supply chains has been a topic for continuous discussions and debates between the policy makers, government (executing) agencies, supply chain operators and cargo owners; and also of high interest for industry (lobby) associations, non-governmental organizations (NGOs), consultants and academics. The private sector with their lobby representatives often fear about “too high” costs of upcoming SCS programs, while governmental policy makers have terrorism fears as their number one concern – this leading into an obvious conflict between the two parties. Some specific questions which have been raised around cost of SCS include the following ones (Edmonson, 2006; Stewart and Mueller, 2008; Kommerskollegium 2008, Hintsa 2006, Hintsa et al., 2009): • How much does security cost for global supply chains, from micro-level ´single company – single supply chain´ measures to macro-level industry sector and nation/region-wide security programs? • What is the cost of ´doing nothing´ or ´having inadequate security in place i.e. cost of realized security incidents, losses, supply chain disruptions etc.? • How can the cost of security be allocated to individual shipments, raw materials, semi-finished goods and final products? In order to answer these questions, especially the first two in the list above, this paper aims to create and test the first conceptual model for assessing costs of SCS in global supply chains. The conceptual model is built based on a comprehensive review in SCS literature, and the test is carried out in a case study with a global tobacco / cigarette manufacturing company. Even though it is obvious that at the end of the day the citizens and consumers are the ones who pay for the ´post-2001 SCS´ – in their tax bills and shopping bills – it is still highly relevant to identify, analyze, categorize and model the various security cost elements in the supply chain. Both governmental policy makers and private sector supply chain and security responsible need objective, solid cost information while minimizing the total spending in security, in terms of prevention plus recovery costs (Hintsa et al., 2010a), and while making scenarios and calculating the return of investment (ROI) values for any types of security investments. Supply chain security management Modern supply chain security management came in to existence in the aftermaths of the infamous 9/11 terrorist attack. Emergent threat of terrorism with rampant transnational crime have changed security paradigm among policy makers and supply chain practitioners and brought supply chain security issues into the limelight. Today, supply chain disruptions are a major concern and responsibility for high level managers all the way up to board rooms (Cavinato, 2004). Escalated importance of supply chain security management has made SCS management an integral part of general supply chain management. As a result, security aspects are not anymore secluded or looked down neither in day-to-day decision making or strategic planning. After a decade of persistent supply chain security management research the academic field is still in its infancy. Despite of the research activity, only a few definitions exists for SCS management. These definitions indicate that coordinated (often interorganizational) management of security tools, techniques and policies are the cornerstone of SCS management. In addition, the SCS management definitions point out the most salient supply chain crime types and the most critical assets to protect. Closs et al. (2004) defines SCS management as “[…] the application of policies, 2
procedures, and technology to protect supply chain assets (product, facilities, equipment, information, and personnel) from theft, damage, or terrorism, and to prevent the introduction of unauthorized contraband, people, or weapons of mass destruction into the supply chain.” Quality management Quality management has the same basic underlying dilemma as SCS: how to allocate resources optimally between prevention versus reactive activities, e.g. process quality, quality inspections and product recalls (Foster, 2004)? No doubt, there is a great opportunity to create value for a company through an optimized security program. Though, just like in quality management, many challenges lie on the road in achieving the optimum allocation of security activities. Minimizing the total cost of SCS management Quality management literature along with two publications (Husdal, 2009; Hintsa et al. 2010b) has been main sources of inspiration for the SCS cost graph (Figure 1). The graph introduces curve of total costs of security (top curve, u-shape) which equals the sum of three cost components: mandatory costs, reactive costs and proactive costs. Mandatory costs are base SCS costs that a company faces inevitably if it desires to keep its business operations running. Reactive costs, representing explicitly costs of bad security, comprise of value of lost security benefits (such as better punctuality of shipments, better staff retention rate etc.), cost of security incidents (value of stolen goods, cost of re-shipments etc.) and cost of non-compliance (lost business opportunities, cost of avoidable inspection fees etc.). Reactive costs tend to decrease when the company invests on security proactively (by implementing new measures and maintaining existing ones). Costs of these up-front investments are labeled as proactive costs. Logically, reactive and proactive costs are negatively correlated i.e. whenever proactive costs increase, reactive costs decrease, respectively (and vice versa). Mandatory costs remain the same regardless of allocation between proactive and reactive costs. Altogether, deep understanding of the three cost groups is necessity in finding the optimal security level.
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Figure 1- Minimizing the total cost of SCS management
Next, each of the proposed three SCS cost groups is matched with specific literature findings, and instantly tested with a real case company and supply chain. The case study company for this paper belongs to five biggest manufacturers in the world for tobacco products. It sources tobacco leafs from three different continents, manufacturers finished products (cigarettes) in over one dozen manufacturing sites, and distributes cigarettes for global markets. The industry sector is cursed with several types of crime related with the global supply chain including theft, counterfeit, customs fraud – and even hijacks, looting and sabotage (see e.g. PMI 2003, PMI 2005, Gutierrez 2007). SCS Proactive costs According to our preliminary definition, proactive SCS costs consist of all investments which are done up-front, i.e. before something happens. A diverse set proactive security costs can be found in current SCS literature – every security standard, guide book and initiative suggest various proactive security measures which induce eventually proactive security costs. Amongst the most obvious security costs are direct technology investments such as asset tracking applications, CCTV-systems and immobilizer solutions for trucks (Rice and Spayd, 2005; Lee and Wolfe, 2003; Palac-McMiken 2005; Sarathy 2006). Besides technology aspects, spending in personnel and supplier selections and security related administration, are regularly highlighted (Rice and Spayd 2003; Erera et al., 2003). Investments in preparedness, which refers to reacting and recovering capabilities, have been frequently lifted on the table by multiple authors (Craighead et al., 2007; Sheffi 2001; Eggers 2004; Russel and Saldanha 2003). One of the most essential topics in the studying field has been voluntary security compliance through security programs such as C-TPAT and EU AEO (Gutierrez and Hintsa, 2006; Diop et al., 2007; Bichou, 2008). Five numeric examples from literature are presented in the Table 1 below. Remarkably, one time investment is not usually enough as security activities require constant funding in terms of salary costs, maintenance and administration. Table 1 - Five numeric examples of proactive SCS costs for facility and cargo security
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Security measure Investment in CCTV system C-TPAT implementation Guards and security maintenance
Cost 70 000 $ one time
Source Quinn 2003, p.3
38471 $ one time; 69000 $ annual operations 58 000 € annually
Diop et al., 2007 p.41 Gutierrez 2007, p.172
Security escort with a truck in Latin America
340 € per trip
Gutierrez 2007, p. 172
Reusable tags Disposable tags
2$ per unit 0,6 $ per unit
Langnau 2003, p.2
Explanation Results: “poorly designed video system” Average with 100´s of US companies Beverage (alcohol) manufacturing company in Latin America Case study with a beverage (alcohol) manufacturer Source: sales manager at FKI Logistex
Regarding proactive security costs at the case company – SCS investments, service procurement, internal labor etc. – a total of 46 security activities were recognized while two headquarter functions (global and national) and five supply chain stages were analyzed with the case company: (1) Inland transport of tobacco leafs from a warehouse to the manufacturing site; (2) Cigarette manufacturing site; (3) Inland transport from the factory to a distribution center; (4) Warehousing and commissioning; and (5) Distribution to the first customer. Following the principles of ABC-modeling (e.g. Bichou, 2004), nine of the total 46 activities are shared in the Table 2 below, relating to stages 1 and 2, as well as to corporate level security management. Table 2 - Nine examples of real security activities in the case supply chain Supply chain stage Security activity 1. Inland transport, 1.1 Install plastic seal on truck warehouse to the manufacturing site 1.2 Use hard body truck for transportation 1.3 Arrange driver training, security aspects 2. Cigarette 2.1 Manage overall security at the factory manufacturing site 2.2 Coordinate guard services, security aspects 2.3 Manage and monitor CCTV-systems ***** Table is cut here ******* 7. Headquarters security 7.1 Manage supply chain security for whole corporate management 7.2 Manage supply chain IT-security for whole corporate 7.3 Manage supply chain security aspects of customs programs
Besides, some other relevant cost management statistics regarding investment profiles, external service procurement, cost allocation (cost object) levels and cost curve shapes over the total of 46 security activities are presented in the Statistics are carried out over the full 46 SCS activity population; not just the nine activities, which are indicated in the previous table (the complete analysis is available per request, together with the full version of the previous security activity table).
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Table 3 below. Statistics are carried out over the full 46 SCS activity population; not just the nine activities, which are indicated in the previous table (the complete analysis is available per request, together with the full version of the previous security activity table). Table 3 - Statistics on cost characteristics over the 46 security activities in the case supply chain Requires multi-year investement Some service bought from outside Primary allocation level
Cost curve shape
Yes No Yes No Corporate Shipment Product Linear Non-linear (other than step-wise) Step-wise
43 % 57 % 52 % 48 % 11 % 24 % 65 % 4% 59 % 37 %
Dynamicity of criminal activities makes it extremely challenging to allocate security budget efficiently. According to SOCA (2009) organized criminal groups are becoming more and more attracted in cargo thefts of high value goods (including finished tobacco products). This trend leads inevitably to more deliberate and ruthless criminal endeavors. When we take a look to case company´s (facility level = stage 2 in the previous table) proactive security budget allocation in one European country in 2006 (Figure 2) we can see that conveyance security takes a lion’s share of overall security budget. The other major target of security spending is facility protection (CCTVsystems and burglar alarms).
Figure 2 - Spread of annual Proactive SCS budget at the case company manufacturing site
SCS Mandatory costs 6
Mandatory costs are, by a preliminary definition, costs that a company faces inevitably if it desires to keep business operations running. High relevance of SCS costs relating to mandatory regulations are highlighted throughout SCS literature (Sarathy, 2006; Erera et al., 2003). Especially, mandatory security programs have been a hot topic due to perceived high costs and vague benefits for the private sector (Kruk and Donner, 2008; Bichou, 2008; Erera et al., 2003; OECD, 2003; Goulielmos and Anastasakos, 2005). Discussion has also been revolving around inspection fees at the borders (Sheu et al., 2006; Bakshi and Gans, 2007; Damas-cesgol, 2001). Besides, unavoidable delays at borders have been considered as expensive grievances in several publications, that is, interest in trade facilitation remains high (Burke, 2005; Williams et al., 2008; Kommerskollegium, 2008; Russel and Saldanha, 2003). Despite of broad qualitative literature considering mandatory SCS cost, there are scarcely quantitative data available. However, Table 4 reveals a snapshot of mandatory SCS cost figures. Table 4 - Five literature based examples of mandatory security costs in supply chains Security measure Cost Source Explanation ISPS implementation 1,1 billion $ one time Bichou 2008 p. Total of 327 official in all US ports cost. 660 million 19 ports of entry (DHS, annual maintenance 2006) cost ISPS costs for US 218 million $ one Bichou 2008, Total of 3500 vessels flagged ships time cost. 178 p.20 million$ annual maintenance 24 hour manifest 43$ per manifest Buck Consultants charge to shippers 2005, p.32 Security charges of Varies between 2 – Bichou 2008, 13 country survey, ports 14$ per container p.24 mainly EU
Regarding mandatory SCS costs for the case company, following observations have been made during the study process. First, the ISPS regulation as well as 24 hour rule have had some minor implications on cost of security for the case company supply chain, in terms of extra security fees by the freight forwarders and carriers (numbers not documented, though). Second, regarding shipment inspection by customs, there was an incident around year 2007 in a Central European country where an export shipment to outside Europe was flagged as a high risk one by the customs administration in charge. They indicated that “if the case company had been EU AEO certified at that time, the likelihood of having such an inspection would have been minimal” - this led into missing two additional sailings, causing inventory handling costs and shipment (re)booking costs; but not customer (non)satisfaction costs (as no-one run out of stocks at the final destination). Third example of mandatory type of SCS costs goes back to year 2004, when the case company signed an agreement with the European Commission and several member countries, committing it to enhance security management, procedures and shipment tracking and authentication capabilities in the fight against illicit trade and smuggling of tobacco products. Besides the costs in personnel, procedures and technologies, the case company agreed to pay a large compensation to EC and the member countries, in the order of magnitude of 1 billion Euros, over a 12 year period. SCS Reactive costs 7
Reactive costs are to be covered after security incidents happen (losses with theft; processing of claims; replacement of damaged materials etc.). In a broader sense, reactive costs can be understood as costs of bad security. No doubt, relying on bad security is gambling – a company wins if it’s lucky enough to avoid security incidents but, on the contrary, financial and reputational losses can be significant if the company undergoes a set major security incidents. A lot of examples regarding reactive security costs can be found in the existing SCS literature. Tangible reactive costs such as lost value of stolen goods, costs of reshipping, contractual penalties are pointed out frequently (Stewart and Mueller, 2008; Lee and Whang, 2005). Reputational issues and possibility of brand erosion have been put forth by several authors. They point out importance of maintaining good (security) image in the eyes of various stakeholders (Sarathy, 2006; Prentice 2008). Costs of supply chain disruptions due to security incidents are a commonly discussed topic as well (Latour, 2001; Closs et al., 2008). Attempt (or even looming threat) of terrorist attack is projected to be costly for supply chain operators without mentioning staggering loss estimates of successful terrorist attack (Bernasek, 2002; White et al., 2004; DNV 2005). Lastly, some concerns are expressed considering penalties and fees which are in connection with non-compliance of security regulations and norms (Baiman et al., 2003).
Table 5 - Five literature based examples of reactive security costs in supply chains Security incident / Cost Source Explanation damage / loss Bio-terrorist attack on Property damage 1 – DNV 2005, p.17 the freight 10 billion $ Direct transportation system disruption to trade 20 – 200 billion $ A high alert situation 60 billion $ until the Booz Allen Hamilton, Simulation triggered and closing of several logistics backlog has 2004 by radioactivity alerts sea ports. been cleared (58 at two US West Coast days) ports Fines due to data 5000 $ for the first Buck Consultants Fines issued by US errors required by 24- violation, 10000$ for 2005, p.30 customs hour rule the second
Regarding reactive costs for the case company: the last two examples with mandatory costs could also be considered as reactive costs, i.e. if there had been an EU AEO certificate in place before (the customs inspection incident) and/or if there had been better security management practices towards anti-smuggling before (the EC agreement incident), one or both of these incidents might not have ever happened. While this of course remains on speculative level, following examples of theft and robberies are non-questionably proper examples of reactive SCS costs at the case company. Table 6 illustrates briefly circumstances and consequences of three crime incidents the case company faced during year 2005. Because dealing with the aftermaths of crime incidents is a highly relevant issue, Table 6 is augmented with a column explaining corrective actions executed after the crime incidents. 8
Table 6 - Three examples of security reactive costs at the case company Type of incident Value of goods Brief description of Corrective actions stolen (including circumstances taxes) Theft of finished 55 000 € Theft by driver of Incident was reported to the tobacco products external transporter police, and the drivers were (1 436 000 during a delivery of found and arrested. cigarettes) cigarettes in Asia. Theft of finished 52 000 € A third party Warehouse security was tobacco products controlled warehouse increased. (2 415 000 was broken into cigarettes) Robbery of 50 000 € Three fake police Training program of finished tobacco officers assaulted a security officers on how to products (1 730 driver and the avoid these types of assaults 000 cigarettes) security guards. was initiated.
Lastly, two other types of costs of SCS were also observed during the case study, not included explicitly in the initial conceptual cost model: (i) Excise tax guarantee / exemption agreements, after signing them between customs and the case company, require certain security standards to be implemented and maintained by the case company, especially regarding facility security. If there was no such agreement in place, then the bank guarantee amounts would be significantly higher, thus causing higher bank fee or interest costs. And (ii) the maritime (cargo) and facility insurances are partially in place due to the crime risks in the supply chain, introducing insurance premium, administration and claim processing costs, amongst other possible SCS costs. Conclusions and future studies This paper presented an attempt to develop and test a holistic model for analyzing various cost factors for securing global supply chains. The demand for such research is evident, and the previous research leaves many gaps. A conceptual model was developed based on literature, classifying cost of security as proactive, mandatory and reactive costs. This model was tested with a global tobacco product manufacturer and supply chain. It appears that the model works relatively well for the overall SCS cost analysis and assessment. However, there were a couple of instances where two groups were partially overlapping (with mandatory versus recovery, regarding government facing efforts), and two security cost items did not directly fit in the model (excise scheme and insurance), thus further work is required in the future. Regarding the bigger picture of a priori and post ante calculation of cost of security in global supply chains, the cost allocations back to products, links with profit and loss statements, security costefficiency assessments, links with the insurance sector, public versus private financing of security discussions, and SCS as a potential technical trade barrier considerations, this paper provides a tested starting point, leaving these topics subject to future research. Acknowledgements The authors would like to express their gratitude for receiving research funding from: European Union Framework Program 7 (FP7), project LOGSEC; Swiss Science Foundation (SNF), and TEKES and Aalto University in Finland. References 9
Baiman et al. (2003), “Procurement of quality in supply chains with a ‘weakest link’. Working Paper, Risk Management and Decision Processes Center, The Wharton School, University of Pennsylvania. Bakshi, N and Gans, N (2007), “Securing the containerized supply chain: an economic analysis of CTPAT”, Wharton School, University of Pennsylvania, Working Paper : 2007-11-19 Bichou, K (2004), “The ISPS Code and The Cost of Port Compliance: An Initial Logistics and Supply Chain Framework for Port Security Assessment and Management”, Maritime Economics & Logistics, No.6, pp. 322-348 Bichou, K (2008), “Maritime security and risk-based models: review and critical analysis” Discussion paper prepared for the OECD/ITF Round Table of 11-12 December 2008 on Security, Risk Perception and Cost-Benefit Analysis. Booz Allen Hamilton port security war game (BAH) 2002 Available on-line on: http://www.boozallen.com Visited on the 1st of April 2004. Buck Consultants International, (2005), “Literature study measures in the supply chain” Burke, R.J. (2005), “International terrorism and threats to security: implications for organizations and management”, Disaster Prevention and Management, Vol. 14, No. 5, pp. 639-43. Cavinato, J (2004), “Supply chain logistics risks: from the back room to the board room”, International Journal of Physical Distribution & Logistics Management, Vol. 34, No. 5, pp. 383-387 Closs, D and McGarrell, E (2004) “Enhancing security throughout the supply chain”. Special report series, IBM Center for The Business of Government, available at: www.businessofgovernment.org Craighead et al. (2007), ”The severity of supply chain disruptions: design for characteristics and mitigation capabilities”, Decision Sciences Institute, Vol. 38, No. 1, pp. 131-156 Damas, P (2001), “Supply chains at war”, American Shipper, November 2001, pp. 17-18 Diop et al. (2007) “Customs-trade partnership against terrorism: cost/benefit survey”, University of Virginia, Report prepared for U.S. Customs and Border Protection. DNV Consulting, (2005), “Study on the impact of possible European legislation to improve transport security”, Final Report: Impact assessment, Report for European commission n° 40008032-6-2 Donner, M and Kruk, C (2008), “Review of cost compliance with the new international freight transport security requirements” Published by the World Bank, Transport Papers n° 44543 Donner, M and Kruk, C (2009), “Supply chain security guide”, World Bank Edmonson, R.G. (2006), “What Price Security”, Journal of Commerce, December 4 2006, p.14 Eggers, W (2004), “Prospering in the secure economy”, Deloitte research study, Deloitte Touche Tohmatsu. Erera, A et al. (2003), ”Cost of Security for sea cargo transport”, The Logistics Institute – Asia Pacific National University of Singapore, Research Paper Foster, Th, 2004, Managing Quality: an integrative approach, Pearson Education International, 2nd Edition, New Jersey Goulielmos, A and Anastasakos, A (2005), “Worldwide security measures for shipping, seafarers and ports” Disaster Prevention and Management, No. 14, pp. 462-478. Gutierrez, X and Hintsa, J (2006), “Voluntary supply chain security programs: a systematic comparison” ILS 2006. The International Conference on Information Systems, Logistics and Supply Chain, Lyon, France, May 15-17 Gutierrez, X (2007), “A Model for the Design of Effective and Resilient Supply Chain Security Management Systems”, Doctoral thesis, University of Lausanne Heimburger, M (2005), “International Risk Management & Insurance 2005 Marine Claims”, Altria Group, Inc. (December 1 2005 presentation) Hintsa et al. (2009), “Supply chain security management: an overview”, International Journal of Logistics Systems and Management, Vol. 5, No. 3-4: 344-355 Hintsa et al. (2010a), “A holistic framework on voluntary SCS programs and standards – tool for analysis and design”, Journal of Transportation Security, Spring 2010 Issue. Hintsa et al. (2010b), “Feasibility study on European supply chain security standards” The European Committee for Standardization (CEN) / TC 379. Kommerskollegium, (2008), “Supply chain security initiatives a trade facilitation perspective” Report is prepared for the Government of Sweden by the administrative body dealing with foreign trade and trade policy. Langnau, L (2003), “Security up in the air”, Transportation & Distribution, Vol. 44, No. 6, pp. 42 Latour, A (2001), “Trial by fire: A blaze in Albuquerque sets off major crisis for cell-phone giants— Nokia handles supply shock with aplomb as Ericsson of Sweden gets burned—Was SISU the difference?”, Wall Street Journal, January 29, A1. Lee, H and Wolfe, M (2003), “Supply chain security without tears.” Supply Chain Management Review January/February 2003, pp.12-20
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Lee, H and Whang, S (2005), “Higher supply chain security with lower cost: Lessons from total quality management”, International Journal of Production Economics, No.96, pp. 289-300 OECD, (2003), “Quantitative assessment of the benefits of trade facilitation” OECD publications Palac-McMiken, E (2005), “Economic Costs and Benefits of Combating Terrorism in the Transport Sector.” Asian-Pacific Economic Literature, Vol. 19, No. 1, pp. 60-71. PMI (2005), “Logistics Standards and Practices: loss prevention in warehousing”, Philip Morris Global Logistics Prentice, B (2007), “Tangible and intangible benefits of transportation security measures” Journal of Transportation Security, Vol. 1, pp. 3-14 Quinn, F (2003), “Security matters”, Supply Chain Management Review, Vol.7, No. 4, pp. 38 Rice, J and Spayd, P (2005), “Investing in supply chain security: collateral benefits.” IBM Center for the Business Government, May 2005, pp.1-30 Russel, D and Saldanha, J (2003), “Five tenets of security-aware logistics and supply chain operation”, Transportation Journal, Vol. 42, No. 4, pp.44-54 Sarathy,R (2006), “Security and the global supply chain.” Transportation Journal, Vol. 45, No.4, pp. 2850 Sheffi,Y (2001), “Supply chain management under the threat of international terrorism”, Massachusetts Institute of technology, Vol.12, No. 2, pp. 1-11 Sheu et al. (2006), “A voluntary logistics security program and international supply chain partnership”, Supply Chain Management: An International Journal, Vol.11, No.4, pp. 363-374 Serious Organized Crime Agency (SOCA), 2009, “Annual Report 2008/2009”. Stewart, M and Mueller, J (2008), “A risk and cost-benefit assessment of United States aviation security measures”, Journal of Transportation Security, Vol. 1, pp. 143–159. White et al. (2004), “A research agenda for supply chain security and productivity”, Working paper, School of Industrial and Systems Engineering, Georgia Institute of Technology. Williams et al.(2008), “Supply chain security: an overview and research agenda”, The International Journal of Logistics Management, Vol.19, No.2, pp. 254 - 281
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