00293nam a2200109Ia 450000500170000008000180001724500760003526000350011130000100014650000080015658300190016420260716043106.0  a16.05.01 C397  aLand and food : the challenge of sustainable agriculture in the tropics  bThe CentreaWageningenNLc1989  a96 p.  aIDS  c3/7/00kM2LMGR