Kuiper Belt -- from Eric Weisstein's World of Astronomy

A putative belt of asteroids beyond the orbit of Neptune. The belt is believed to be composed of material which formed in situ in the outer solar system and has remained at its current orbital distance over the lifetime of the solar system by being captured in a stable resonance with Neptune. Edgeworth (1949) and Kuiper (1951) were the first to suggest that a belt of consolidate material could exist beyond Neptune's orbit, and Fernandez (1980) suggested that this belt could be the source of short-period comets. This conclusion was supported by the numerical simulations of Duncan et al. (1988), who found that a flattened distribution of outer solar system bodies could reproduce the observed orbital parameters of short-period comets.

Arnett, W. "The Nine Planets: The Kuiper Belt and the Oort Cloud." Nine Planets.

Cochran, A. L.; Levison, H. F.; Stern, S. A.; and Duncan, M. J. "The Discovery of Halley-Sized Kuiper Belt Objects." Astrophys. J. 455, 342, 1995.

Duncan, M.; Quinn, T.; and Tremaine, S. "The Origin of Short-Period Comets." Astrophys. J. Let. 328, L69-L73, 1988.

Edgeworth, K. E. Mon. Not. Roy. Astron. Soc. 109, 600-609, 1949.

Fernandez, J. A. Mon. Not. Roy. Astron. Soc. 192, 481-491, 1980.

Jewitt, D. "Kuiper Belt." http://www.ifa.hawaii.edu/~jewitt/kb.html.

Kuiper, G. P. In Astrophysics (Ed. J. A. Hynek). New York: McGraw-Hill, pp. 357-424, 1951.