Cita APA (7th ed.)

Plumbe, A. J., & Byrne, H. M. (1981). The role of the agricultural tractor in road haulage in Sri Lanka. Transport and Road Research Laboratory.

Cita Chicago (17th ed.)

Plumbe, A. J., i H. M. Byrne. The Role of the Agricultural Tractor in Road Haulage in Sri Lanka. Crowthorne, Berkshire: Transport and Road Research Laboratory, 1981.

Cita MLA (9th ed.)

Plumbe, A. J., i H. M. Byrne. The Role of the Agricultural Tractor in Road Haulage in Sri Lanka. Transport and Road Research Laboratory, 1981.