@MISC{10665-67643, author = {Presthus, Garry T and Sibiya, J. B}, title = {Un foyer persistant de variole au Botswana, 1973 / par G.T. Presthus et J.B. Sibiya}, year = {1974}, pages = {WHO/SE/74.69}, publisher = {Organisation mondiale de la santeĢ} }