00267nam a22001097a 4500003000500000038001300005082001800018100001700036245005300053260004300106300000800149NUST  aM.Ramzan  a628.5028bKHO  aKhopkar, S.M  aEnvironmental pullotion analysis /cS.M. khopkar  aNew DelhibNew Age Internationalc1993  a244