1. Aaeonson, S., Deangelis, B., Frank, O., Baker, H.: Secretion of vitamins and amino acids into the environment byOchromonas-danica. — J. Phycol.7: 215–218, 1971.
2. Cablucci, A. F., Bowes, P. M.: Production of vitamin B12, thiamine and biotin by phytoplankton. — J. Phycol.6: 351–357, 1970.
3. Carr, N. G.: Metabolic control and autotrophic physiology. — In:Carb, N. G., Whitton, B. A. (ed.): The Biology of Blue-green Algae, Botanical Monograph. Vol.9. Pp. 39–65. Blackwell Scientific Publ., Oxford 1973.
4. Cheng, K. H., Miller, A. G., Colman, B.: An investigation of glycollate excretion in two species of blue-green algae. — Planta103: 110–116, 1972.
5. Daisley, K. W.: Monthly survey of vitamin B12 concentration in some waters of the English lake district. — Limnol. Oeeanogr.14: 222–228, 1969.