Lengeler, C; Kessler, W; Daugla, D. "The 1990 meningococcal meningitis epidemic of Sarh (Chad): how useful was an earlier mass vaccination?". Acta Trop59: 211–22. doi:10.1016/0001-706x(95)00081-o. PMID7572427.
Lengeler, C; Kessler, W; Daugla, D. "The 1990 meningococcal meningitis epidemic of Sarh (Chad): how useful was an earlier mass vaccination?". Acta Trop59: 211–22. doi:10.1016/0001-706x(95)00081-o. PMID7572427.