Bagnall, K. W. (1967). „Recent advances in actinide and lanthanide chemistry”. u: Fields, P.R.; Moeller, T.. Advances in chemistry, Lanthanide/Actinide chemistry. Advances in Chemistry. 71. American Chemical Society. str. 1–12. DOI:10.1021/ba-1967-0071. ISBN0-8412-0072-6.
Pauling, L. (1932). „The Nature of the Chemical Bond. IV. The Energy of Single Bonds and the Relative Electronegativity of Atoms”. Journal of the American Chemical Society54 (9): 3570–3582. DOI:10.1021/ja01348a011.