@ARTICLE {VERSTEEG:1993, title = {Participative farmer testing of four low external input technologies, to address soil fertility decline in Mono Province( Benin)}, author = {Versteeg, M. and Koudokpon *, V. }, journal = {Agricultural Systems}, year = {1993}, volume = {42}, number = {2}, pages = {265--276}, issn = {0308-521X}, }