K. Agarwal, Suresh, and Manohar Lal. “Structural Investigations on Co(II), Ni(II) and Cu(II) Biligand Coordination Compounds With 7-Hydroxy-4-Phenyl-6-(Α-Naphthyl)-Aminomethyl Coumarin As Primary and 4-Nitroso-1-Hydroxy-2-Naphthoic Acid As Secondary Ligand ”. Asian Journal of Chemistry, vol. 10, no. 4, Mar. 2010, pp. 1051-3, https://asianpubs.org/index.php/ajchem/article/view/23787.