@MANUAL {MUTSAERS:1997, title = {A field guide for on-farm experimentation}, author = {Mutsaers, H. J. W. and Weber, G. and Walker, P. and Fischer, N. }, year = {1997}, organization = {IITA; CTA; ISNAR}, note = {On Farm Research; General; Learning Material; ISBN: 978-131-125-8; 235p.}, }