C. Walker, und H. Wiesenfeld. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, (April 2007)PMID: 17342664.
J. Reed, J. Thistlethwaite, und J. Huppert. The Journal of Adolescent Health: Official Publication of the Society for Adolescent Medicine, 41 (1):
14--18(Juli 2007)PMID: 17577529.