1. Astronomically observable crater-forming projectiles;Shoemaker,1977
2. Collision of astronomically observable bodies with the earth;Wetherill,1982
3. Terrestrial impact rates for long and short-period comets;Weissman,1982
4. Cratering constraints on the inner Oort cloud: steady-state models;Bailey;Mon. Not. R. Astron. Soc.,1988
5. The cometary impactor flux at the earth;Weissman,1989