Halley, J. Woods
How likely is extraterrestrial life?
[Springer, ], 2012
 eBooks
Life on earth
by Edwad O. Wilson ... [et.al.]
Sinauer Associates, 1973
 Buku Teks
Jones, H. Spencer
Life on other worlds
Macmillan, 1956
 Buku Teks
Achenbach, Joel
Captured by aliens: the search for life and truth in a very large universe
Simon & Schuster, 1999
 Buku Teks
Communication with extraterrestrial intelegence
edited by J. Billingham and
Pergamon Press, 1979
 Buku Teks SO