“Spectrophotometric Determination of Co(II) in Vitamin B12 Using 2-(biphenyl-4-Yl)-3-((2-(2,4-Dinitrophenyl) hydrazono)methyl) Imidazo [1,2-a]pyridine As Ligand by Flow Injection–Merging Zone Analysis”. Al-Nahrain Journal of Science, vol. 23, no. 3, Sept. 2020, pp. 24-38, https://mail.anjs.edu.iq/index.php/anjs/article/view/2309.