Edwards, Allen L.
Holt, Rinehart and Winston, 1964
Buku Teks
Munro, Barbara Hazard, author
Lippincott, 1986
Buku Teks
Cohen, Lillian, author
Prentice-Hall, 1955
Buku Teks
Morrison, Donald F., author
McGraw-Hill International Book Company, 1983
Buku Teks
Morrison, Donald F., author
McGraw-Hill, 1990
Buku Teks