00344nam a2200121 a 450000500170000002000150001708200130003210000150004524500430006026000480010330000210015150000500017220251203110048.0  a8176480193  a577bNAY  aNayar, K.R  aEcology and healthba systems approach  aNew DelhibAPH publishing corporationc1998  a210p.c22cm.bHB  aincludes bibliographical references and index