A. Sullivan, J. Wigginton, and D. Kirschner. Proceedings of the National Academy of Sciences of the United States of America, 98 (18):
10214--10219(August 2001)PMID: 11517319.
E. Koumans, R. Johnson, J. Knapp, and M. Louis. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 27 (5):
1171--1180(November 1998)PMID: 9827265.