United States. Forest Service. North Pacific Region. Public Relations Office. (1932). What is forestry?: An outline for classes in economics, geography and nature study in high schools of Washington.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)United States. Forest Service. North Pacific Region. Public Relations Office. What Is Forestry?: An Outline for Classes in Economics, Geography and Nature Study in High Schools of Washington. Portland, 1932.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)United States. Forest Service. North Pacific Region. Public Relations Office. What Is Forestry?: An Outline for Classes in Economics, Geography and Nature Study in High Schools of Washington. 1932.
Cảnh báo: Các trích dẫn này có thể không phải lúc nào cũng chính xác 100%.