1. B. Arnold, J. Michl, in: M. Platz (Ed.), Kinetics and Spectroscopy of Carbenes and Biradicals, Plenum, New York, 1989.
2. Ab initio calculations on the energy of activation and tunneling in the automerization of cyclobutadiene
3. A multireference coupled‐cluster study of the ground state and lowest excited states of cyclobutadiene
4. J.C. Sancho-Garcı́a, J. Pittner, P. Čársky, I. Hubač (1999), submitted.
5. V.I. Minkin, M.N. Glukhovtsev, B.Ya. Simkin, Aromaticity and Antiaromaticity. Electronic and Structural Aspects, Wiley, New York, 1994.