R. Brooks, C. Woods, D. Benjamin, and N. Rosenstein. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 43 (1):
49--54(July 2006)PMID: 16758417.
P. Stefanoff, M. Rosinska, G. Karczewski, and A. Zielinski. Euro Surveillance: Bulletin Européen Sur Les Maladies Transmissibles = European Communicable Disease Bulletin, (March 2008)PMID: 18445440.