Abou-Hadeed, Khaled. “Formation of Substituted Benzo[a]heptalenes via Bergman Cyclization of Vicinal Di(ethynyl)-Heptalenes”. CHIMIA 54, no. 12 (December 20, 2000): 763. Accessed April 20, 2024. https://www.chimia.ch/chimia/article/view/2000_763.