1. Biological and Chemical terrorism; strategic plan for preparedness and response recommendations of the CDC strategic planning Workgroup;CDC;MMWR,2000
2. Ricin a Possible Non-Infectious Biological Weapon;Maman,2009
3. Yemen: Barack Obama warned that al-Qaeda planning ricin attack;Goddard;The Telegraph,2011
4. Of beans and beads: ricin and abrin in bioterrorism and biocrime;Roxas-Duncan;J. Bioterr. Biodef.,2012
5. Tests indicate poison in senate mail room of majority leader;Hulse;N.Y. Times,2004