Sleema, B., and Geetha Parameswaran. 2012. “X-Ray Diffraction Studies of Iron(II), Nickel(II) and Copper(II) Complexes of O-Vanillin-L-Histidine”. Asian Journal of Chemistry 14 (2):961-66. https://asianpubs.org/index.php/ajchem/article/view/22244.