1. Akabane, K. 1983, Int. J. Infrared Millim. Waves 4, 793
2. Baars, J.W.M. 1984, in Infrared and Millimeter Waves, Vol. 9, ed., K.J. Button, Academic Press, New York-London, p. 241
3. Baars, J.W.M., Hooghoudt, B.G. 1974, Astron. Astrophys. 31, 323
4. Bennet, J.C., Anderson, A.P., McInnes, P.A., Whitaker, A.J.T. 1976, IEEE Trans. Ant. Prop. Ap 24, 295
5. Brownless, C.R. 1966, LSA, p. 364