Hester, J. J. (2002). 21st century astronomy. New York: Norton.
Chicago Style aipamenaHester, John Jeffrey. 21st Century Astronomy. New York: Norton, 2002.
MLA aipamenaHester, John Jeffrey. 21st Century Astronomy. New York: Norton, 2002.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.