@INPROCEEDINGS {VOGEL:1989, title = {Economic returns of alley farming}, author = {Vogel, W. O. and Mutsaers, H. J. W. }, booktitle = {Alley farming in the humid and subhumid tropics, proceedings edited by B.T. Kang; L. Reynolds}, year = {1989}, pages = {197--207}, publisher = {IDRC}, address = {Ottawa}, }