Cupitt, Don
Sheldon Press, 1979
Buku Teks SO
Panchen, Alec L.
Cambridge University Press, 1994
Buku Teks
Odum, Howard T.
McGraw-Hill, 1981
Buku Teks SO
Niebuhr, Reinhold
Charles Scribners Sons, 1945
Buku Teks SO
Cornwell, Alan
McGraw-Hill, 1974
Buku Teks SO