* Walter P. Calahan Photography, Inc., copyright 2008. Homepage banner and other photos of
the Virginia Division of Consolidated Laboratory Services (VA DCLS), Richmond, VA.
http://www.walterpcalahan.com/Cheers/Home.html
^ Wisconsin State Laboratory of Hygiene.
~ University of Iowa Hygienic Laboratory.
+ Minnesota Department of Health, Public Health Laboratory.
# Public Health Image Library, Centers for Disease Control
% Stock photograph