00246nam a2200109Ia 4500008004100000041000800041082001800049100001600067245003600083260000900119300000800128211209s1969    xx            000 0 und d  aeng  a631.7 N77 MIC  aMICHAEL A M  aIRRIGATION THEORY AND PRACTICE   c1969  a801