Gibbon, Edward
Random House , 1993
Buku Referensi
Gibbon, Edward
Random House, 1994
Buku Referensi
Troxel, Ronald L., author
Wiley-Blackwell, 2012
Buku Teks
edited by, Frank Gaynor
Philosophical Library, 1953
Buku Referensi
Mott, George Fox
Barnes & Noble, Inc., 1957
Buku Teks