00422nam a2200097Ia 4500008004100000082002200041100005300063245014500116260005500261300000800316140113s9999    xx            000 0 und d  a631.62(02)   L3.1  a"U.S.Dept. of Agric., Soil Conservation Service"  a"Drinage of agricultural land : A practical handbook for the planning, design, construction and maintenance of agricultural drinage systems"  a1973b"Water Information Centre, Inc."cWashington  a430