1. Cameron, Wm. M.: 1948, Rapid Oxygen-Absorbed Test, Inst. Sewage Purif., J. and Proc., Pt. 1, 228.
2. Foulds, J. M. and Lunsford, J. V.: 1968, Water Sewage Works
115(3), 112.
3. Howland, W. E.: 1943, Sewage Works J.
15, 512.
4. Ivekovic, H. and Gertner, A.: 1953, Anal. Chim. Acta
7, 396.
5. Jansa, V. and Akerlindh, G.: 1941, Sewage Works J.
13, 551.