JHA, R.R., and D.K. JHA. “Preparation and Characterization of Tin(II) and Tin(IV) Complexes With Some Morpholine-N-Thiocarbazones ”. Asian Journal of Chemistry, vol. 15, no. 1, Mar. 2010, pp. 428-34, https://asianpubs.org/index.php/ajchem/article/view/21566.