Hopfen, H. J. (1962). Farm implements for arid and tropical regions (Rev. ed.). F.A.O..
Cita Chicago (17th ed.)Hopfen, H. J. Farm Implements for Arid and Tropical Regions. Rev. ed. Rome: F.A.O., 1962.
Cita MLA (8th ed.)Hopfen, H. J. Farm Implements for Arid and Tropical Regions. Rev. ed. F.A.O., 1962.
Atenció: Aquestes cites poden no estar 100% correctes.