Não informado. (1944). Drilling contractor. American Association of Oilwell Drilling Contractors.
Cita Chicago Style (17a ed.)Não informado. Drilling Contractor. Dallas, Tex: American Association of Oilwell Drilling Contractors, 1944.
Cita MLA (8a ed.)Não informado. Drilling Contractor. American Association of Oilwell Drilling Contractors, 1944.
Precaución: Estas citas no son 100% exactas.