^Giacomo, Bruzzone. Compounds of erbium with metalloids of Groups V and VI. Atti Accad. Nazl. Lincei, Rend., Classe Sci. Fis. Mat. Nat., 1961. 31: 260-264. CAN57: 9184.
^Tikhonova, N. N. Kinetics of the oxidation of rare-earth phosphides. Izvestiya Vysshikh Uchebnykh Zavedenii, Khimiya i Khimicheskaya Tekhnologiya, 1971. 14 (3): 464-465. ISSN0579-2991.