Bordetella pertussis seroprevalence in Belgian adults aged 20-39 years, 201234005, Huygen, K, Rodeghiero C, Govaerts D., Leroux-Roels G., Melin P., Reynders M., Van Der Meeren S., Van Den Wijngaert S., and Piérard Denis , Epidemiol.Infect., 0/4/2014, Volume 142, Issue 4, Number 728, p.724 - 728, (2014)