TY  - RPRT
TI  - Geologic map of the Topton quadrangle, Lehigh and Berks Counties, Pennsylvania
AU  - Avery Ala Drake
PY  - 1987
DO  - 10.3133/gq1609
UR  - https://pubs.usgs.gov/publication/gq1609
ID  - gq1609
ER  -