Cita APA (7th ed.)

Dowling, J. W. F., Franco L., R., & Russell, R. B. C. (1982). Natural asphalts: Their occurrence, properties and use in road construction in Columbia. Transport and Road Research Laboratory.

Cita Chicago (17th ed.)

Dowling, J. W. F., Rudolfo Franco L., i R. B. C. Russell. Natural Asphalts: Their Occurrence, Properties and Use in Road Construction in Columbia. Crowthorne, Berkshire: Transport and Road Research Laboratory, 1982.

Cita MLA (9th ed.)

Dowling, J. W. F., et al. Natural Asphalts: Their Occurrence, Properties and Use in Road Construction in Columbia. Transport and Road Research Laboratory, 1982.