Cita APA (7th ed.)
Hester, J. J. (2007). 21st century astronomy (2nd ed.). W.W. Norton.
Cita Chicago (17th ed.)
Hester, John Jeffrey. 21st Century Astronomy. 2nd ed. New York: W.W. Norton, 2007.
Cita MLA (9th ed.)
Hester, John Jeffrey. 21st Century Astronomy. 2nd ed. W.W. Norton, 2007.
Atenció: Aquestes cites poden no estar 100% correctes.