Cooper, G. P. a. R. (1931). The Evergreen Forests of Liberia.: A report on investigation made in the west african republic of liberia by the yale university school of forestry in cooperation with the firestone plantations company. Yale University.
Chicago-referens (17:e uppl.)Cooper, G. Proctor and Recorc. The Evergreen Forests of Liberia.: A Report on Investigation Made in the West African Republic of Liberia by the Yale University School of Forestry in Cooperation with the Firestone Plantations Company. New Haven: Yale University, 1931.
MLA-referens (9:e uppl.)Cooper, G. Proctor and Recorc. The Evergreen Forests of Liberia.: A Report on Investigation Made in the West African Republic of Liberia by the Yale University School of Forestry in Cooperation with the Firestone Plantations Company. Yale University, 1931.