A. Petsas, A. Sharma, O. Aghadiuno, M. Abid, and K. Paranthaman. Euro Surveillance: Bulletin Européen Sur Les Maladies Transmissibles = European Communicable Disease Bulletin, (January 2008)PMID: 18445400.
F. Fusco, and V. Puro. Euro Surveillance: Bulletin Européen Sur Les Maladies Transmissibles = European Communicable Disease Bulletin, (March 2008)PMID: 18445438.
J. Bigham, M. Hutcheon, D. Patrick, and A. Pollard. Canada Communicable Disease Report = Relevé Des Maladies Transmissibles Au Canada, 27 (2):
13--8(January 2001)PMID: 11227821.