TY  - GEN
AU  - Verschuur , Gerrit L.
TI  - Impact : the threat of comets and asteroids
SN  - 0195119193
U1  - 523.6 
PY  - 1996///
CY  - Oxford
PB  - Oxford University Press
KW  - COMETS
KW  - ASTRONOMY
KW  - ASTEROIDS
ER  -