S. Shehab, N. Keller, A. Barkay, L. Leitner, A. Leventhal, and C. Block. European Journal of Clinical Microbiology & Infectious Diseases: Official Publication of the European Society of Clinical Microbiology, 17 (11):
749--53(November 1998)PMID: 9923513.
O. Bilukha, and N. Rosenstein. MMWR. Recommendations and Reports: Morbidity and Mortality Weekly Report. Recommendations and Reports / Centers for Disease Control, 54 (RR-7):
1--21(May 2005)PMID: 15917737.