Adams, Roger, 1889-1971, author
McMillan, 1963
Buku Teks
Doxsee, Kenneth M., author
Thomson, Brooks/Cole, 2004
Buku Teks
Rodiq, Oscar R., author
Fort Worth Saunders, 1990
Buku Teks
Seager, Spencer L., author
Thomson Brooks/Cole, 2008
Buku Teks
Bailey, Philip S., author
Allyn and Bacon, 1978
Buku Teks