1. H. A. C. McKAY, Principles of radiochemistry. Butterworths, London, 1971, p. 296.
2. R. BYRON BIRD, W. E. STEWART, E. N. LIGHTFOOT, Transport Phenomena, Wiley International Edition, New York, 1960, p. 621.
3. N. LAHAV, G. H. BOLT, Soil Sci., 97 (1964) 293.
4. P. MÖLLER, C. S. SASTRI, Z. Phys. Chem. Neue Folge, 89 (1974) 80.
5. Measurements performed at the Institute for Earth Sciences, State University at Utrecht.