APA

Liebner W., Koempel H., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. & Koempel H.Gas to propylene. : .

Chicago

Liebner W, Koempel H, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Koempel H.Gas to propylene. : .

Harvard

Liebner W., Koempel H., World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro B. and Koempel H.Gas to propylene. : .

MLA

Liebner W, Koempel H, World Petroleum Congress (17th. : 2002 sept. 1-5 : Río de Janeiro Brasil) and Koempel H.: . .