Nicolson, Iain
The universe
Horus Editions, 1995
Buku Referensi
Oparin, A.
The universe
Foreign Languages Publishing House, 1960
Buku Teks
Brittan, Arthur
Meanings and Situations
Routledge & Kegan Paul, 1973
Buku Teks SO
The universe grasper
Artikel Jurnal
Krauskopf, Konrad B.
The physical universe
McGraw-HIll, 2000
Buku Teks SO