1. Bartoli, F.: 1983, ?Invertebrate Mineralization?, in Environmental Biogeochemistry, Proc. 5th Intl. Symp. Env. Biogeochem. (ISEB) Ecol. Bull. (Stockholm) 35, 469.
2. Bowen, H. J.: 1966, Trace Elements in Biochemistry, Acad. Press, London.
3. Elvin, D.: 1972, Exptl. Cell Res. 72, 551.
4. Lewin, J.: 1966, Phycologia 6,1.
5. Lewin, J. and Reimann, B.: 1969, Ann. Rev. Plant Physiol. 20, 289.