Wolfe, Gerard R., author
McGraw-Hill, 1994
Buku Referensi
edited by Robert Moore Fisher
Doubleday, 1955
Buku Teks
Castillo, Carlos, 1889-1967, compiler
The University of Chicago Press, 1948
Buku Referensi
Eric A. Posner
Ashgate/Dartmouth, 2001
Buku Teks
The University of Chicago Press, 2010
Buku Teks