Nehrt, Lee Charles
International Textbook, 1967
Buku Teks
Nehrt, Lee Charles
Intext Educational, 1972
Buku Teks
Harris, J. Manville.
Barron's Educational Series, 1992
Buku Teks
Wasserman, Max J.
D.C. Health and Company, 1966
Buku Teks
Ward, Richard
Prentice-Hall, 1965
Buku Teks