@BOOK {COUPER:1994a, title = {La construction et l'entretien des routes dans les stations experimentales: Guide de recherche de I'iita No. 20}, author = {Couper, D. C. }, series = {Guide de recherche de I'iita No. 20}, year = {1994}, month = {March}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {19p.}, }