Held, G. creator text New Delhi Sams Publishing 1996 monographic xvii,430p. Data Communications 004.6HEL 8120310802 (paperback) 9788120310803 (paperback) http://www.amazon.com/exec/obidos/ASIN/8120310802/chopaconline-20 http://www.amazon.com/exec/obidos/ASIN/8120310802/chopaconline-20