C. Walker, und H. Wiesenfeld. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, (April 2007)PMID: 17342664.
L. Haddow, C. Mulgrew, A. Ansari, J. Miell, G. Jackson, H. Malnick, und G. Rao. Clinical Microbiology and Infection: The Official Publication of the European Society of Clinical Microbiology and Infectious Diseases, 9 (5):
426--30(Mai 2003)PMID: 12848758.