000 00277nam a2200121Ia 4500
008 180721s9999 xx 000 0 und d
100 _aC.R.W. SPEDDING
245 0 _aBIOLOGICAL EFFICIENCY IN AGRICULTURE
260 _bNil
260 _c1981
365 _b50.00
942 _cBK
999 _c165038
_d165038