MCGRAW-HILL. (1992). Mcgraw-hill encyclopedia of science and technology 8: GEO-HYS. McGraw-Hill.
Cita Chicago (17th ed.)MCGRAW-HILL. Mcgraw-hill Encyclopedia of Science and Technology 8: GEO-HYS. New York: McGraw-Hill, 1992.
Cita MLA (9th ed.)MCGRAW-HILL. Mcgraw-hill Encyclopedia of Science and Technology 8: GEO-HYS. McGraw-Hill, 1992.
Atenció: Aquestes cites poden no estar 100% correctes.