1. Tang A., Kiang Y., Yan G., Tai S.: Graph Theoretical Molecular Orbitals. Science Press, Beijing (1986)
2. Bloch F.: Quantenmechanik der Electronen in Kristallgittern. Zeit. Physik 52(7–8), 555–600 (1928)
3. London F.: Théorie quantique des courants interatomiques dans les combinaisons aromatiques. J. Phys. Radium 8(10), 397–409 (1937)
4. E. Heilbronner, H. Bock, The HMO Model and Its Application, Vol. 3.Verlag Chemie, Weinheim, 1968 and 1978 (in German); Wiley, London, (in English) (1976)
5. Aihara J.: Topological resonance energy, bond resonance energy, and circuit resonance energy. J. Am. Chem. Soc. 98, 2750–2758 (1976)