1. Customs and Border Protection (CBP). Border patrol history. Department of Homeland Security. 2010. Available at: 〈http://www.cbp.gov/xp/cgov/border_security/border_patrol/border_patrol_ohs/history.xml〉, 2012 (accessed on 25.01.12).
2. Earls Industries, Limited. Products: shipping & container handling. 2012. Available at: 〈http://earlsindustries.com/products/shipping/#〉 (accessed on 09.04.12).
3. Mutable detector array software for the detection of emissions in classrooms and the field (Thesis);Hearn,2012
4. ORTEC. DigiBASE-E high-performance, digital gamma spectrometer. Ametek. Available at: 〈www.ortec-online.com/download/DigiBASE-E.pdf〉, 2013 (accessed on 07 05.2013).
5. United States Department of Transportation (US DOT). America's container ports: delivering the goods. Technical Report, Research and Innovative Technology Administration. 2007.