1. Non-Benzenoid Aromatic Compounds (ed. by D. Ginsburg). New York: Wiley 1959.
2. Jones, A. J.: Rev. Pure Appl. Chem.18, 253 (1968).
3. Badger, G. M.: Aromatic Character and Aromaticity. London: Cambridge Univ. Press 1969.
4. Nonbenzenoid Aromatics (ed. by J. P. Snyder). New York: Academic Press; Vol. 1, 1969; Vol. 2, 1971.
5. Aromaticity, Pseudo-Aromaticity. Anti-Aromaticity (ed. by E. D. Bergmann and B. Pullman). Jerusalem: Israel Acad. Sci. Hum. 1971.