APA استشهاد

Engelbert, P. (1997). Astronomy and Space: From the Big Bang to the Big Crunch. U. X. L.

استشهاد بنمط شيكاغو

Engelbert, Phillis. Astronomy and Space: From the Big Bang to the Big Crunch. New York: U. X. L, 1997.

MLA استشهاد

Engelbert, Phillis. Astronomy and Space: From the Big Bang to the Big Crunch. U. X. L, 1997.