1. See e.g.: H. C. van de Hulst, Light Scattering by Small Particles, John Wiley and Sons, Inc., New York;
2. R. Newton, Scattering Theory of Waves and Particles, McGraw-Hill Book Co., New York 1966;
3. M. Kerker, The Scattering of Light and other Electromagnetic Radiation, Academic Press, New York 1969.
4. See e.g.: C. Eftimiu, Direct and Inverse Scattering by a Sphere of Variable Index of Refraction, J. Math. Phys. Vol 23, pp. 2140–2146, 1982, and the references given therein.