1. Bellamy, L. J.: 1966,Infra-red Spectra of Complex Molecules, Wiley, New York, 425 pp.
2. Chen, Y., Senesi, N. and Schnitzer, M.: 1978,Geoderma 20, 87.
3. De Serra, M. I. and Schnizer, M.: 1973,Can. J. SoilSci. 52, 93.
4. De Serra, M. I. and Schnitzer, M.: 1973,Soil Biol. Biochem.,5, 281.
5. Organic Components;W. Flaig,1975