Husain, Asif, et al. “Synthesis and Biological Evaluation of 2-Arylidene-4-(4-Methoxy-phenyl)but-3-En-4-Olides”. Asian Journal of Chemistry, vol. 17, no. 3, May 2016, pp. 1579-84, https://asianpubs.org/index.php/ajchem/article/view/14036.