Cita APA

Hester,Jeff, & Hester, J. J. (2007). 21st century astronomy (2nd ed.). New York: W.W. Norton.

Chicago Style Citation

Hester,Jeff, i John Jeffrey Hester. 21st Century Astronomy. 2nd ed. New York: W.W. Norton, 2007.

Cita MLA

Hester,Jeff, i John Jeffrey Hester. 21st Century Astronomy. 2nd ed. New York: W.W. Norton, 2007.