1. Oxidation of tartaric acid by manganic sulphate in sulphuric acid medium and by hexaquomanganese(III) ion in noncomplexing medium of perchloric acid;Barek;Coll. Czech. Chem. Commun,1978
2. A survey of the oxidizing properties of tervalent manganese compounds with respect to their analytical use (in Czech);Barek;Chem. Listy,1975
3. Barek, J., Berka, A., and Hladíková, A., Oxidation of pyruvic acid with manganese(III) sulphate in a medium of sulphuric acid and with hexaquomanganese(III) ions in a noncomplexing medium of perchloric acid. Microchem. J., 316–322.
4. The preparation and stability of standard solution of tervalent manganese;Barek;Chem. Anal. (Warsaw),1975
5. Oxidation of citric acid by manganic sulphate in sulphuric acid medium;Barek;Coll. Czech. Chem. Commun,1979