Mardia T. El Sayed, et al. “Novel Aspects of Domino Reaction of Indoles With Homo- Phthalaldehyde and Tere-Phthalaldehyde”. Global Journal of Science Frontier Research, vol. 14, no. B6, May 2014, pp. 15-21, https://journalofscience.org/index.php/GJSFR/article/view/1332.