TY  - RPRT
TI  - Large-magnitude Middle Ordovician volcanic ash falls in North America and Europe: Dimensions, emplacement and post-emplacement characteristics
AU  - W.D. Huff
AU  - Dennis R. Kolata
AU  - Stig M. Bergstrom
AU  - Y.-S. Zhang
PY  - 1996
UR  - https://pubs.usgs.gov/publication/70018055
ID  - 70018055
ER  -