Karim, N. H., S.A. AI- Nuaimi, and N. S. Nassory. 2017. “Potentiometric Analysis of Samarium Ion in Aqueous Solution Employing Selective Electrode Based on Crown Ethers - Samarium Picrate Complexes in a PVC Membrane”. Ibn AL-Haitham Journal For Pure and Applied Sciences 19 (3): 117-33. https://jih.uobaghdad.edu.iq/index.php/j/article/view/1653.