1. Ponnamperuma, C. (ed.): 1981, Comets and the Origin of Life, D. Reidel.
2. Wilkening, L.L. (ed.): 1981, Comets, Univ. Arizona Press.
3. Delsemme, A.H. (ed.): 1977, Comets, Asteroids, and Meteorites, Univ. Toledo Bookstore.
4. Donn, B., Mumma, M., Jackson, W., A’Hearn, M., and Harrington, R. (eds.): 1976, The Study of Comets, NASA SP-393.
5. Whipple, F.L. and Huebner, W.F.: 1976, “Physical Processes in Comets”, in Ann. Rev. Astron. Astrophys. 14, pp. 143–172.