APA

Needham D., Hartman K., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. & Hartman K.E-Business within E&P. : .

Chicago

Needham Donnie, Hartman Ken, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Hartman Ken.E-Business within E&P. : .

Harvard

Needham D., Hartman K., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. and Hartman K.E-Business within E&P. : .

MLA

Needham Donnie, Hartman Ken, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Hartman Ken.: . .