Cita APA (7th ed.)
Ojakangas, R. W., & Matsch, C. L. (1982). Minnesota's geology. University of Minnesota Press.
Cita Chicago (17th ed.)
Ojakangas, Richard W., i Charles L. Matsch. Minnesota's Geology. Minneapolis: University of Minnesota Press, 1982.
Cita MLA (9th ed.)
Ojakangas, Richard W., i Charles L. Matsch. Minnesota's Geology. University of Minnesota Press, 1982.
Atenció: Aquestes cites poden no estar 100% correctes.