Artikel Jurnal
edited by Harold C. Gardiner
Devin-Adair Co., 1949
Buku Teks
Robert Maynard Hutchins, editor in chief
Encyclopaedia Britannica, Inc., 1952
Buku Referensi
Goethe, Johann Wolfgang von
Christian Wegner Verlag, 1967
Buku Teks
Keller, Helen Rex
McMillan Company, 1959
Buku Referensi