TY  - RPRT
TI  - Statistics of petroleum exploration in the non-Communist world outside the United States and Canada
AU  - David H. Root
AU  - Emil D. Attanasi
AU  - Robert M. Turner
PY  - 1987
DO  - 10.3133/cir981
UR  - https://pubs.usgs.gov/publication/cir981
ID  - cir981
ER  -