Heller, R. L. (1979). Earth science (2d ed.). Webster Division, McGraw-Hill.
Citación estilo ChicagoHeller, Robert L. Earth Science. 2d ed. New York: Webster Division, McGraw-Hill, 1979.
Cita MLAHeller, Robert L. Earth Science. 2d ed. Webster Division, McGraw-Hill, 1979.
Warning: These citations may not always be 100% accurate.