1. Letters carried fresh anthrax. Baltimore Sun. June 23, 2002. Available at: http://articles.baltimoresun.com/2002-06-23/news/0206230062_1_anthrax-spores-powder-leahy.
2. Massive cross-contamination feared. New York Daily News. October 26, 2001. Available at: https://www.nydailynews.com/archives/news/anthrax-found-top-city-mail-center-massive-cross-contamination-feared-article-1.934574.
3. Lengel A. Little progress in FBI probe of anthrax attacks. Washington Post. Available at: http://www.washingtonpost.com/wp-dyn/content/article/2005/09/15/AR2005091502456_pf.html.
4. President Bush signs Project Bioshield Act of 2004. Available at: www.whitehouse.gov.
5. The powder: from Berlin to Brazil, the ‘anthrax’ letters;Erlanger;New York Times,2001