Latif, I. K., and E.S. Hassan. “The Effect of Four Lateral Methyl Groups on The Thermotropic Behavior of Azo Liquid Crystal Homologous Series”. Ibn AL-Haitham Journal For Pure and Applied Sciences, vol. 23, no. 1, May 2017, pp. 260-71, https://jih.uobaghdad.edu.iq/index.php/j/article/view/1005.