1. Black, C. A.: 1965, Methods of Soil Analysis, Am. Soc. Agron. Monogr. No. 9, Madison, Wisconsin.
2. Cheam, V. and Gable, D. S.: 1974, Can. J. Soil. Sci.
54, 413.
3. Friberg, L., Piscator, M., and Nordberg, G. F.: 1974, Cadmium in the Environment, Chemical Rubber Co., Cleveland, Ohio.
4. Hiatt, V. and Huff, J. E.: 1975, Intern. J. Environ. Studies
7, 227.
5. John, M. K., Van Laerhoven, C., and Chuah, H. H.: 1972, Environ. Sci. Technol.
6, 555.