1. M. Abramowitz, I.A. Stegun, Chapter 26, in Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables (Dover, New York, 1965), p. 946. ISBN 978-0486612720
2. F. Allard, P.H. Hauschildt, D. Schwenke, Astrophys. J. 540, 1005 (2000)
3. R.J. Allison, S.P. Goodwin, R.J. Parker, S.F. Portegies Zwart, R. de Grijs, Mon. Not. R. Astron. Soc. 407, 1098 (2010)
4. I. Appenzeller, R. Mundt, Astron. Astrophys. Rev. 1, 291 (1989)
5. M. Asplund, N. Grevesse, A.J. Sauval, in Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis, vol. 336, p. 25 (2005)