APA

Johnson A., Letszch W., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. & Letszch W.Emerging technologies in the petrochemical refinery. : .

Chicago

Johnson A.R, Letszch W.S, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Letszch W.S.Emerging technologies in the petrochemical refinery. : .

Harvard

Johnson A., Letszch W., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. and Letszch W.Emerging technologies in the petrochemical refinery. : .

MLA

Johnson A.R, Letszch W.S, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Letszch W.S.: . .