Nievergelt, B. Ibexes in an African environment : ecology and social system of the Walia ibex in the Simen Mountains, Ethiopia / B.Nievergelt. - Berlin : Springer-Verlag , 1981. - ix ,189 p. : ill. ; 25 cm. - Ecological studies v.40. . Bibliography: p.179-186. ISBN: 3540105921 Subjects--Topical Terms: Bouquetin.Mammals--Ethiopia--Simen Mountains.