TY  - RPRT
TI  - Statistics of petroleum exploration in the world outside the United States and Canada through 2015
AU  - Emil D. Attanasi
AU  - Philip A. Freeman
PY  - 2019
DO  - 10.3133/cir1450
UR  - https://pubs.usgs.gov/publication/cir1450
ID  - cir1450
ER  -