@MISC {VAN ASTEN:2010b, title = {Improving soil fertility through intercropping}, author = {Van Asten, P. }, year = {2010}, month = {March}, howpublished = {Workshop paper presented at COPAL workshop, Kumasi, Ghana, 16-18 March}, note = {An oral presentation at the COPAL workshop on Soil management for sustainable cocoa production in Kumasi, Ghana, 16-18 March 2010. 12p.}, }