| 000 | nam a22 4500 | ||
|---|---|---|---|
| 020 | _a | ||
| 245 | _aFarming systems principles : for improved food production and the control of soil degradation in the arid, semi-arid, and humid tropics | ||
| 260 |
_aKenya _bUnited Nations environment programmer _cc1986 |
||
| 710 | _aInternational Crops Research Institute for the semi-arid Tropics | ||
| 942 | _c22 | ||
| 999 |
_c6742 _d6742 |
||