B. Jülg, J. Elias, A. Zahn, S. Köppen, C. Becker-Gaab, und J. Bogner. Journal of Travel Medicine: Official Publication of the International Society of Travel Medicine and the Asia Pacific Travel Health Association, 15 (2):
133--6(2008)PMID: 18346250.
D. Livermore. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 34 (5):
634--40(März 2002)PMID: 11823954.
M. Bonten, D. Austin, und M. Lipsitch. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 33 (10):
1739--46(November 2001)PMID: 11595995.