American Geological Institute & Department of Science and Technology(DOST). (1992). Geology: Rocks that form on the earth's surface. Encyclopedia Britannica Educational Corporation.
Chicago-referens (17:e uppl.)American Geological Institute och Department of Science and Technology(DOST). Geology: Rocks That Form on the Earth's Surface. Chicago, Ill: Encyclopedia Britannica Educational Corporation, 1992.
MLA-referens (9:e uppl.)American Geological Institute och Department of Science and Technology(DOST). Geology: Rocks That Form on the Earth's Surface. Encyclopedia Britannica Educational Corporation, 1992.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.