00305nam a22001217a 4500003000500000020002100005038001100026082001500037100001700052245005700069260004600126300001100172NUST  a8171582796qH/B.  awaseem  a333.7bTRI  aTrivedi, P R  aEncyclopedia of Environmental Science /cP R Trivedi  aNew Delhi :bAkashdeep Publishing,c1992.  a278 p.