↑ [Peter Andreas: Redrawing the line 2003:92], additional text.
↑ Perl, Raphael (2004)."The Department of Homeland Security: Background and Challenges", Terrorism—reducing Vulnerabilities and Improving Responses, Committee on Counterterrorism Challenges for Russia and the United States, Office for Central Europe and Eurasia Development, Security, and Cooperation Policy and Global Affairs, in Cooperation with the Russian Academy of Sciences, page 176. National Academies Press. ISBN 0-309-08971-9.
