Le Brefon, Preston P.
Holt, Rinehart and Winston, 1965
Buku Teks
Le Breton, Preston P.
Prentice-Hall, 1961
Buku Teks
Le Breton, Preston P.
Englewood Cliffs, 1961
Buku Teks
Walters, Jack Edward
Littlefield, Adams, 1959
Buku Teks
Kilgannon, Pete, author
McGraw-Hill, 1980
Buku Teks