Christopherson, R. W. (1995). Elemental geosystems: A foundation in physical geography. Prentice Hall.
Lua i Stíl Chicago (17ú heag.)Christopherson, Robert W. Elemental Geosystems: A Foundation in Physical Geography. Englewood Cliffs, N.J.: Prentice Hall, 1995.
Lua MLA (8ú heag.)Christopherson, Robert W. Elemental Geosystems: A Foundation in Physical Geography. Prentice Hall, 1995.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.