Leroy, G., Wilante, C., Peeters, D., & Uyewa, MM. (1985). A Theoretical Investigation of the Properties of Carbocations and Carbanions. Journal of Molecular Structure: THEOCHEM, 25(1-2), 107-131. https://doi.org/10.1016/0166-1280(85)87024-X (Original work published 1985)