(5th ed, John Wiley 1988) p.625 Haire, Richard G. "Fermium, Mendelevium, Nobelium and Lawrencium". In Morss; Edelstein, Norman M.; Fuger, Jean. (3rd ed.)
2nd edn, Prentice-Hall, p. 16 Haire, Richard G. "Fermium, Mendelevium, Nobelium and Lawrencium". In Morss; Edelstein, Norman M.; Fuger, Jean. (3rd ed.)