U. Lorenz, M. Abele-Horn, D. Bussen, and A. Thiede. Langenbeck's Archives of Surgery / Deutsche Gesellschaft Für Chirurgie, 392 (6):
761--765(November 2007)PMID: 17661075.
B. Jülg, J. Elias, A. Zahn, S. Köppen, C. Becker-Gaab, and 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.