By Abdul Rehman Khalid

Published by The Carvan book house, 1987

By Arthur Beiser

Published by Mc Graw-Hill book co., 1987

By Arthur Beiser

Published by McGraw Hill, 2003

By Paul G. Hewitt

Published by 14-Local Shopping Centre, Panchsheel Park, 2009

By J.R.W. Warn

Published by ELBS, 1985

Published by Oxford Science Publications, 1985

Published by Oxford University Press, 1985

Published by Oxford University Press, 1985

By Kirk-Othmer

Published by John wiley and sons, 1985

By Prof. Iqbal A Bhatti

Published by Bhatti Publishers, 1991