@BOOK {PLEYSIER:1991, title = {Echantillonnage du sol et preparation des echantillons: Guide de recherche de I'iita, No. 2}, author = {Pleysier, J. L. }, series = {Guide de recherche de I'iita, No. 2}, year = {1991}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {26p.}, }