Oparin, A.
The universe
Foreign Languages Publishing House, 1960
Buku Teks
Nicolson, Iain
The universe
Horus Editions, 1995
Buku Referensi
Brittan, Arthur
Meanings and Situations
Routledge & Kegan Paul, 1973
Buku Teks
Abell, George O.
Exploration of the universe
Holt Rinehart and Winston, 1974
Buku Teks
Exploration of the universe
Buku Teks