1.
Pollutant Effects in Freshwater
by Welch, Eugene B., Jacoby, J...
ISBN: 9780415429900
List Price: $63.00
2.
Ecological Effects of Waste Water - E. B. Welch - Hardcover
by Welch, Eugene B., Lindell, T.
ISBN: 9780521224956
List Price: $19.95