| Reference Label | Details |
|---|---|
| Bieri 1977 | G. Bieri, F. Burger, E. Heilbronner and J. P. Maier, Helv. Chim. Acta 60, 2213-2233 (1977) Valence Ionization Energies of Hydrocarbons |
| Heilbronner 1971 | E. Heilbronner, R. Gleiter, H. Hopf, V. Hornung, and A. De Meijere, Helv. Chim. Acta 54, 783-794 (1971) Photoelectron-Spectroscopic Evidence for the Orbital Sequence in Fulvene and 3,4-Dimethylenecyclobutene |