S. Suyanta, S. I.R, B. Buchari, and I. Noviandri, “Preparation and Characterization of Lanthanum (III) Selective Electrode Based on 1,10-Diaza-4,7,13,16-Tetraoxacyclooctadecane-N,N’-Diacetic Acid as an Ionophore”, JPMS, vol. 11, no. 1, pp. 181–187, May 2012.