G. A. Meshram, S. S. Deshpande, V. A. Vala, and P. A. Wagh, “Indion 190 resin: Reusable catalyst for the synthesis of quinoxalines and pyrido-pyrazines at ambient temperature”, Eur. J. Chem., vol. 4, no. 4, pp. 422–424, Dec. 2013.