Seeds, M. A. (1990). Foundations of astronomy (1990 edition.). Wadsworth Publishing Company.
Cita Chicago (17th ed.)Seeds, Michael A. Foundations of Astronomy. 1990 edition. Belmont, California: Wadsworth Publishing Company, 1990.
Cita MLA (8th ed.)Seeds, Michael A. Foundations of Astronomy. 1990 edition. Wadsworth Publishing Company, 1990.
Atenció: Aquestes cites poden no estar 100% correctes.