Stokes, W. L., & Judson, S. (1968). Introduction to geology, physical and historical. Prentice-Hall.
Lua i Stíl Chicago (17ú heag.)Stokes, William Lee, agus Sheldon Judson. Introduction to Geology, Physical and Historical. Englewood Cliffs, N.J: Prentice-Hall, 1968.
Lua MLA (9ú heag.)Stokes, William Lee, agus Sheldon Judson. Introduction to Geology, Physical and Historical. Prentice-Hall, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.