Viehe, H.G., G.J. de Voghel, and F. Smets. “Pyridines and Quinolines from 1,3-Dichloro-Trimethinecyanines Pyrimidine and Quinazoline from Azacyanine”. CHIMIA 30, no. 3 (March 31, 1976): 189. Accessed April 5, 2025. https://www.chimia.ch/chimia/article/view/1976_189.