Beck, Charles E.
Prentice-Hall, 1999
Buku Teks
Munter, Mary
Prentice-Hall, 1982
Buku Referensi
Veech, Annette M.
Prentice-Hall, 2002
Buku Teks
Ewald, Helen Rothschild
Prentice-Hall International, 1997
Buku Teks
Locker, Kitty O.
McGraw-Hill/Irwin, 2000
Buku Teks