American Institute of Professional Geologists. (1979). The Professional geologist. American Institute of Professional Geologists.
Chicago-Zitierstil (17. Ausg.)American Institute of Professional Geologists. The Professional Geologist. [Golden, Colo.]: American Institute of Professional Geologists, 1979.
MLA-Zitierstil (9. Ausg.)American Institute of Professional Geologists. The Professional Geologist. American Institute of Professional Geologists, 1979.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.