APA

Bull S., Marmin A., Shell, World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest), Marmin A. & Shell.Lube oil manufacture by severe hydrotreatment. : .

Chicago

Bull S, Marmin A, Shell, World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest), Marmin A and Shell.Lube oil manufacture by severe hydrotreatment. : .

Harvard

Bull S., Marmin A., Shell, World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest), Marmin A. and Shell.Lube oil manufacture by severe hydrotreatment. : .

MLA

Bull S, Marmin A, Shell, World Petroleum Congress (10th : 1979 sept. 9-14 : Bucharest), Marmin A and Shell.: . .