@BOOK {CLAASSEN:1993, title = {Travail minimum mecanise et culture sans labour en station experimentale: Guide de recherche de l'Iita, No. 11}, author = {Claassen, S. L. }, series = {Guide de recherche de l'Iita, No. 11}, year = {1993}, month = {July}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {19p.}, }