Gaya APA
Encyclopedia Americana 21 Orley to Photographic Telescope. (1974).
USA:
Americana Corporation.
Gaya Chicago
Encyclopedia Americana 21 Orley to Photographic Telescope.
Vol. 21.
USA:
Americana Corporation,
1974.
Text.
Gaya MLA
Encyclopedia Americana 21 Orley to Photographic Telescope.
Vol. 21.
USA:
Americana Corporation,
1974.
Text.
Gaya Turabian
Encyclopedia Americana 21 Orley to Photographic Telescope.
USA:
Americana Corporation,
1974.
Print.