Duncan, M.; Quinn, T.; Tremaine, S. (1987). "The Formation and Extent of the Solar System Comet Cloud". The Astronomical Journal. 94: 1330. Bibcode:1987AJ.....94.1330D. doi:10.1086/114571.
Duncan, M.; Quinn, T.; Tremaine, S. (1987). "The Formation and Extent of the Solar System Comet Cloud". The Astronomical Journal. 94: 1330. Bibcode:1987AJ.....94.1330D. doi:10.1086/114571.