J. Kharodawala, Mohammad, and Arjun K. Rana. “Study on Oximino-3-Methyl-1-(2´ ,4&Acute; -Dinitrophenyl)-2-Pyrazolin-5-One As a Gravimetric Reagent for Co(II), Ni(II) and Cu(II) ”. Asian Journal of Chemistry, vol. 14, no. 2, Mar. 2010, pp. 979-84, https://asianpubs.org/index.php/ajchem/article/view/22247.