TY  - GEN
AU  - Muller,R A
TI  - Comet showers, periodic extinctions, and iridium
SN  - 0036-8075
PY  - 2010///0702
N1  - Publication Type: Journal Article
UR  - https://doi.org/10.1126/science.234.4783.1484-a
ER  -