TY  - RPRT
TI  - Geology of Bulgaria: A review
AU  - Richard M. Foose
AU  - Frank T. Manheim
PY  - 1975
DO  - 10.1306/83d91c81-16c7-11d7-8645000102c1865d
UR  - https://pubs.usgs.gov/publication/70207490
ID  - 70207490
ER  -