Yang, W. (1965). Methods Of Farm Management Investigations For Improving Farm Productivity (Revised Edition.). FAO.
Lua i Stíl Chicago (17ú heag.)Yang, W.Y. Methods Of Farm Management Investigations For Improving Farm Productivity. Revised Edition. Rome: FAO, 1965.
Lua MLA (9ú heag.)Yang, W.Y. Methods Of Farm Management Investigations For Improving Farm Productivity. Revised Edition. FAO, 1965.