Helvetas -Yaounde, CM

Yaounde, C.M.Helvetas -, Helvetas -Zurich, CH, Swiss Association for International Cooperation & Gallen, C.H.S.K.A.T.-St., 1985. Manual for rural water supply : with many detailed constructional scale-drawings 5th ed.ᵉ éd., St. Gallen, Switzerland: SKAT (Swiss Centre for Development Cooperation in Technology and Management).