V.I.Spitsyn; A.D.Gelman; N.N.Krot; M.P.Mefodiyeva; F.A.Zakharova; Yu.A.Komkov; V.P.ShilovI.; V.Smirnova (1968). "Heptavalent state of neptunium and plutonium". Journal of Inorganic and Nuclear Chemistry (dalam bahasa English). Institute of Physical Chemistry of the Academy of Sciences of the USSR. 31 (9): 2733–2745. doi:10.1016/0022-1902(69)80187-9.Pemeliharaan CS1: Bahasa yang tidak diketahui (link)