Tasić, A., I. Sredović Ignjatović, L. Ignjatović, I. Anđelković, M. Antić, and L. Rajakovic. “Investigation of Different Extraction Procedures for the Determination of Major and Trace Elements in Coal by ICP-AES and Ion Chromatography”. Journal of the Serbian Chemical Society, vol. 81, no. 4, May 2016, pp. 403–417, doi:10.2298/JSC150429078T.