Hogins, J. Burl
Harper & Row, 1969
Buku Teks
edited by Duddley Bailey
W.W. Norton, 1965
Buku Teks
St. Martin's press, 1981
Buku Teks
Encyclopaedia Britannica, Inc. ; Funk & Wagnalls Co., 1961
Buku Referensi
Encyclopaedia Britannica, Inc. ; Funk & Wagnalls Co., 1961
Buku Referensi