Moerland W, Koeman SC, van den Hoek A, Warris-Versteegen AA, Inspector H, Overbosch D, et al: The quality of travel clinics in the Netherlands. J Travel Med 13: 356-360, 2006.
Steffen R, Rickenbach M, Wilhelm U, Helminger A, Schär M. Health problems after travel to developing countries. J Infect Dis 156: 84-91, 1987.
CDC Health Information for International Travel 2014.