00321nam a2200109Ia 4500008004100000082001700041100002300058245005000081260003200131300001000163650003800173140113s9999    xx            000 0 und d  a620.91:63 M0  a" Pimentel, David"  aHandbook of energy utilization in agriculture  b"Florida : CRC press, 1980"  a475p.  aEnergy utilization in agriculture