00290nam a2200109Ia 450000500170000000800410001708200150005810000160007324500370008926000460012630000080017220260224041012.0260224s9999||||xx |||||||||||||| ||und||  a631.45 HEL  aHeld, R.B.  0aSoil conservation in perspective  aBaltimore, Published for Resources c1965  a341