00325pam a2200121 a 4500020001000000041000500010082001200015100003400027245008700061250001200148260003500160300000800195  aNILc  h  a333.707  aDeswal S. & Deswal A.eAuthor  aA Basic Course in Environmental StudiescDeswal S. & Deswal A.hTextual Documents   a2nd Ed.  bDhanpat Rai Publicationsc2012  a255