Kubát, J. The sphericity effects in the NLTE model atmospheres of white dwarfs. ISBN 0-7923-4585-1. In: ISERN, J., HERNANZ, M., GARCIA-BERRO, E., eds. White Dwarfs. Dordrecht: Kluwer Academic Publishers, 1997, s. 229-235. Astrophysics and Space Science Library.