Burton, W. M.; Evans, R. G. (1976), Slettebak, Arne (ed.), "Spectroscopic Observations of the Be Stars η Cen, γ Cas and Φ Per", Be and Shell Stars, International Astronomical Union/Union Astronomique Internationale, Springer Netherlands, pp. 199–207, doi:10.1007/978-94-010-1498-4_27, ISBN9789401014984{{citation}}: CS1 maint: work parameter with ISBN (link)