Undiscovered oil in the US
USGS
2008-04
<a rel="nofollow" class="external free" href="https://certmapper.cr.usgs.gov/data/noga00/natl/graphic/2008/total_oil_mean_08.pdf">http://certmapper.cr.usgs.gov/data/noga00/natl/graphic/2008/total_oil_mean_08.pdf</a>