@BOOK {COUPER:1991,
title = {Leves topographiques pour les stations de recherche: Guide de recherche de l'Iita, No. 1},
author = {Couper, D. C. },
series = {Guide de recherche de l'Iita, No. 1},
year = {1991},
publisher = {International Institute of Tropical Agriculture (IITA)},
address = {Ibadan, Nigeria},
note = {39p.},
}