1. Azpiazu, M. N., Romero, F. and Diaz, J. M.: 1986,Water, Air, and Soil Pollut. 28, 1.
2. Baig, M. B., Ali, S., Ranjha, A. M., Ghafoor A. and Tahir, M. B.: 1987,Pak. J. Sci. Ind. Res. 30(9), 657.
3. Barona, A. and Romero, F.: 1996,Toxicol. Environ. J. (in press).
4. Barona, A., Romero, F. and Elejalde, C.: 1995,J. Haz. Mat. 42, 289.
5. Blakemore, L. C., Searle, P. L. and Daly, B. K.: 1977, A.Methods for Chemical Analysis of Soils, New Zealand Soil Bureau, pp. A1.1–A13.3.