@book{4070,
	author = {International Astronomical Union and International Astronomical Union Symposium and Chebotarev, G. A., ed. and International Astronomical Union},
	title = {The Motion, evolution of orbits, and origin of comets},
	publisher = {D. Reidel Publishing},
	year = {1972},
	series = {IAU Symposium; no. 45},
	address = {Dordrecht}
}