Simple procedure for the determination of Cd, Pb, As and Se in biological samples by electrothermal atomic absorption spectrometry using colloidal Pd modifierViitak, Anu; Volynsky, Anatoly B.Talanta2006 / 4, p. 890-895 : illhttps://www.sciencedirect.com/science/article/pii/S0039914006001330