M. Awadallah, Ramadan. 2010. “Conductometric and Spectrophotometric Studies on Copper(II), Zinc(II) and Cadmium(II) Complexes Of 4-(2-Pyridylazo) Resorcinol ”. Asian Journal of Chemistry 4 (3):511-17. https://asianpubs.org/index.php/ajchem/article/view/25090.