Sana, M., Leroy, G., & Henriet, C. (1989). Theoretical-study of B2hn (with N=2 To 6) - Molecules and Related Positive-ions. Journal of Molecular Structure: THEOCHEM, 56, 233-250. https://doi.org/10.1016/0166-1280(89)85164-4 (Original work published 1989)