TY  - RPRT
TI  - Occurrence and significance of marine animal remains in American coal balls
AU  - S.H. Mamay
AU  - E. L. Yochelson
PY  - 1962
DO  - 10.3133/pp354i
UR  - https://pubs.usgs.gov/publication/pp354I
ID  - pp354I
ER  -