Lovejoy, Laurence C., author
Aleander Hamilton Institute, 1962
Buku Teks
Yoder, Dale, author
McGraw-Hill, 1958
Buku Teks
Yoder, Dale, author
Prentice-Hall, 1984
Buku Teks
Yoder, Dale, author
Prentice-Hall, 1962
Buku Teks
edited by Max S. Wortman
Allyn and Bacon , 1970
Buku Teks