A. Kuijper, Y. Zhou, and B. Heise. VISAPP (1), page 307-314. INSTICC - Institute for Systems and Technologies of Information, Control and Communication, (2008)
C. Fijen, E. Kuijper, M. te Bulte, M. Daha, and J. Dankert. Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 28 (1):
98--105(January 1999)PMID: 10028078.