Related Clues:

• OPEC product
• Wildcatter's strike
• "There Will Be Blood" focus
• Refinery flow
• Biggest export of 99-Down
• The Da Vinci coat?
• Kind of slick
• Canadian resource
• Source of Rockefeller's wealth
• Gusher flow
• Slick material
• Many a MoMA piece
• Upton Sinclair novel
• Rockefeller's biz
• ''Crude'' fuel