SONDHEIMER, F. Nonbenzenoid Aromatic π-Electron Systems. CHIMIA, [S. l.], v. 28, n. 4, p. 163, 1974. DOI: 10.2533/chimia.1974.163. Disponível em: https://www.chimia.ch/chimia/article/view/1974_163. Acesso em: 6 apr. 2025.