APA

Parra F., Petróleos de Venezuela P., World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest) & Petróleos de Venezuela P.World producing capacity of hydrocarbons. : .

Chicago

Parra F.R, Petróleos de Venezuela PDVSA, World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest) and Petróleos de Venezuela PDVSA.World producing capacity of hydrocarbons. : .

Harvard

Parra F., Petróleos de Venezuela P., World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest) and Petróleos de Venezuela P.World producing capacity of hydrocarbons. : .

MLA

Parra F.R, Petróleos de Venezuela PDVSA, World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest) and Petróleos de Venezuela PDVSA.: . .