Kučera, J., Mader, P., Miholová, D., Száková, J., Stejskalová, I., Štěpánek, V. Proficiency tests using four batches of green alga with controlled levels of cadmium. Fresenius Journal of Analytical Chemistry and Fresenius Zeitschrift fur Analytische Chemie. 1998, 360(-), 439-442. ISSN 0937-0633.