DE HEUSCH, L., et al.: Utotombo, Brussels, 1988; Fagg, W.: tribes and forms in african art, Paris, 1965; Vogel, S. and N'Diaye, F.: African Masterpieces from The Musée de l'Homme, New York, 1985; Berjonneau, G. and Sonnery, J.-L.: Chefs-d'Oeuvre Inédits, Paris, 1987; and 12 other books of similar interest (16)