S. DAVE, SHIKHA, and ANJALI M. RAHATGAONKAR. “Commercial Alum PEG 400 Catalyzed Efficient Synthesis of Substituted 2-Phenyl-4H-Chromen-4-Ones by Microwave Irradiation”. Asian Journal of Chemistry, vol. 21, no. 6, Mar. 2010, pp. 4301-6, https://asianpubs.org/index.php/ajchem/article/view/18165.