Effect of tsetse control on trypanosome prevalence in livestock: problems of experimental design and statistical interpretation—A case study in northern Côte d'Ivoire - Rowlands, G.J.; Coulibaly, L.; Hecker, P.A.; D'Ieteren, G.D.M.; Leak, S.G.A.; Authié, Edith (Elsevier, 1996)