Sampathkumar, N., and S.P. Rajendran. “Functionalization of Quinolines: Preparation of 2-Formyl-4-Methoxy Quinolines”. Asian Journal of Chemistry, vol. 16, no. 3, June 2016, pp. 1931-3, https://asianpubs.org/index.php/ajchem/article/view/14440.