Mortimer J. Adler, editor in chief
Encyclopedia Britanica, 1994
Buku Referensi
Artikel Jurnal
edited by Harold C. Gardiner
Devin-Adair Co., 1949
Buku Teks
Shaffira Diraprana Gayatri
2014
UI - Skripsi (Membership)
Keller, Helen Rex
McMillan Company, 1959
Buku Referensi