Aranson, Peter H.
Winthrop, 1981
Buku Teks SO
John Sikula, senior editor ; Thomas Buttery, editor, Edith Guyton, editor
Macmillan Library Reference, 1996
Buku Referensi
Berger, Eugenia Hepworth
Charles E. Merrill, 2000
Buku Teks
Spring, Joel
McGraw-Hill, 2008
Buku Teks SO
Spring, Joel
McGraw-Hill, 2004
Buku Teks SO