Fagg, W.: Tribes and forms in African Art, New York, 1965; Leuzinger, E.: Die Kunst von Schwarz-Afrika, Zurich, 1970; Sweeney, E.: African Negro Art, New York, 1935; Clawson, P.: By Their Works illustrated from the Collections in the Buffalo Museum of Science, Buffalo, 1941; Allemand, M.: L'Art de l'Afrique Noire et "L'Époque Nègre" de Quelques Artistes Comtemporains, Saint-Étienne, 1956; Bassani, E.: La Grande Scultura dell'Africa Nera, Florence, 1989; and thirty-two others of similar interest (38)