Davis, W. M., & Johnson, D. W. (1909). Geographical essays. Ginn and company.
Lua i Stíl Chicago (17ú heag.)Davis, William Morris, agus Douglas Wilson Johnson. Geographical Essays. Boston, New York: Ginn and company, 1909.
Lua MLA (8ú heag.)Davis, William Morris, agus Douglas Wilson Johnson. Geographical Essays. Ginn and company, 1909.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.