APA استشهاد

Brown, G. D., & Ladd, G. T. (1960). The earth: : man's geologic environment. Merrill publishing company.

استشهاد بنمط شيكاغو

Brown, George D., و George T. Ladd. The Earth: : Man's Geologic Environment. Columbus: Merrill publishing company, 1960.

MLA استشهاد

Brown, George D., و George T. Ladd. The Earth: : Man's Geologic Environment. Merrill publishing company, 1960.