edited by Louis G. Locke, William M. Gibson, George Arms
Holt, Rinehart and Winston, 1959
Buku Teks
W.W. Norton & Company, 1977
Buku Teks
Mortimer J. Adler, editor in chief
Encyclopedia Britanica, 1994
Buku Referensi
edited by Harold C. Gardiner
Devin-Adair Co., 1949
Buku Teks
Campbell, Oscar James
Crofts, 1947
Buku Teks