1. Acton, L. W. 1996, in ASP Conf. Ser. 109, Cool Stars, Stellar Systems, and the Sun: Ninth Cambridge Workshop , ed. R. Pallavicini & A. K. Dupree (San Francisco: ASP), 45
2. Allen, C. W. 1973, Astrophysical Quantities (3d ed.; London: Athlone)
3. Abundances of the elements: Meteoritic and solar
4. Evolution of the solar ionizing flux