A. Petsas, A. Sharma, O. Aghadiuno, M. Abid, and K. Paranthaman. Euro Surveillance: Bulletin Européen Sur Les Maladies Transmissibles = European Communicable Disease Bulletin, (января 2008)PMID: 18445400.
C. Walker, and H. Wiesenfeld. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, (апреля 2007)PMID: 17342664.