TY  - RPRT
TI  - The Martinsburg Formation (Middle and Upper Ordovician) in the Delaware Valley, Pennsylvania-New Jersey
AU  - Avery Drake
AU  - Jack B. Epstein
PY  - 1967
DO  - 10.3133/b1244h
UR  - https://pubs.usgs.gov/publication/b1244H
ID  - b1244H
ER  -