1. A&A Special Edition: First Results from ISO (1996) A&A, 315(2).
2. Agarwal, V.K. et al (1985) Origins of Life, 16, 21.
3. Aitken, D.K. (1981), in Wynn-Williams, C.G. and Cruikshank, D.P. (eds.), Infrared Astronomy, D. Reidel Pub. Co., Dordrecht, p. 207.
4. Allamandola, L.J. (1996), in Greenberg, J.M. (ed.), The Cosmic Dust Connection, Kluwer Academic Pub., Dordrecht, p.81.
5. Allamandola, L.J., Bernstein, M.P. and Sandford, S.A. (1997), in Cosmovici, C.B., Bowyer, S. and Werthimer, D. (eds.), Astronomical and Biochemical Origins and the Search for Life in the Universe, Editrice Compositori of the Italian Physical Society, Bologna, p.23.