Gopka, Vera F.; et al. (December 2004). Zverko, J.; et al. (eds.). On the radioactive shells in peculiar main sequence stars: the phenomenon of Przybylski's star. The A-Star Puzzle, held in Poprad, Slovakia, July 8-13, 2004. IAU Symposium, No. 224. Cambridge, UK: Cambridge University Press. pp. 734–742. Bibcode:2004IAUS..224..734G. doi:10.1017/S174392130500966X.
Gopka, Vera F.; et al. (December 2004). Zverko, J.; et al. (eds.). On the radioactive shells in peculiar main sequence stars: the phenomenon of Przybylski's star. The A-Star Puzzle, held in Poprad, Slovakia, July 8-13, 2004. IAU Symposium, No. 224. Cambridge, UK: Cambridge University Press. pp. 734–742. Bibcode:2004IAUS..224..734G. doi:10.1017/S174392130500966X.