Savić, I., G. Nikolić, I. Savić, S. Zlatković, and D. Djokić. “New, Simple and Validated UV-Spectrophotometric Methods for the Estimation of Sodium Usnate in Preparations”. Macedonian Journal of Chemistry and Chemical Engineering, vol. 29, no. 2, Dec. 2010, pp. 157-64, doi:10.20450/mjcce.2010.162.