Não informado. (1956). Practical Power Farming. British Power Farming Club.
Chicago-viite (17. p.)Não informado. Practical Power Farming. London: British Power Farming Club, 1956.
MLA-viite (8. p.)Não informado. Practical Power Farming. British Power Farming Club, 1956.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.