Heltai, György, Ilona Fekete, Gábor Halász, Katalin Kovács, Márk Horváth, Anita Takács, Norbert Boros, and Zoltán Győri. 2015. “Multi-Elemental Inductively Coupled Plasma-Optical Emission Spectroscopic Calibration Problems of the Sequential Extraction Procedure for the Fractionation of the Heavy Metal Content from Aquatic Sediments”. Hungarian Journal of Industry and Chemistry 43 (1):7-13. https://doi.org/10.1515/hjic-2015-0002.