Gaya APA
Seeds, M, A., Backman, D, E.
(2016).
Stars and galaxies
(
9th ed.)
.
Massachusetts:
Cengage Learing.
Gaya MLA
Seeds, Michael, A.., Backman, Dana, E..
"Stars and galaxies".
9th ed.
Massachusetts:
Cengage Learing,
2016.
Text.