1. Adams, T.F. and Frisch, P.C. (1977). High-resolution observations of the Lyman alpha sky background. Astrophysical Journal, 212, 300–308.
2. Ajello, J.M., Witt, N. and Blum, P. (1979). Four UV observations of the interstellar wind by Mariner 10 -Analysis with spherically symmetric solar radiation models. Astronomy and Astrophysics, 73, 260–271.
3. Axford, W.I. (1972). The interaction of the solar wind with the interstellar medium. In C.P. Sonett, P.J. Coleman, Jr., and J.M. Wilcox (eds.), Solar Wind, NASA SP-308, Washington, DC, p. 609.
4. Axford, W. I. (1985), Solar Physics, Vol. 100, p. 575–586.
5. Axford, W.I. (1990). Introductory lecture -The heliosphere. In S. Grzedzielski and D.E. Page (eds), Physics of the Outer Heliosphere, COSPAR Colloquia Series, Vol. 1, Pergamon Press, London, pp. 7–15.