Robert Maynard Hutchins, editor in chief
Encyclopaedia Britannica, Inc., 1952
Buku Referensi
Artikel Jurnal
Mortimer J. Adler, editor in chief
Encyclopedia Britanica, 1994
Buku Referensi
Murray, Gilbert
Oxford University Press, 1946
Buku Teks
Sophocles, author
London Everyman Publishers PLC 1994,
Buku Teks