APA

Duda J., Graham L., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. & Graham L.Meeting the natural gas challenges. : .

Chicago

Duda J.R, Graham L.E, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Graham L.E.Meeting the natural gas challenges. : .

Harvard

Duda J., Graham L., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. and Graham L.Meeting the natural gas challenges. : .

MLA

Duda J.R, Graham L.E, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Graham L.E.: . .