Heltai, G.; Fekete, I.; Halász, G.; Kovács, K.; Horváth, M.; Takács, A.; Boros, N.; Győri, Z. 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. Hung. J. Ind. Chem. 2015, 43, 7-13.