Boies, David.
Little, Brown, 1977
Buku Teks
Presser, Stephen B.
Thomson/West, 2010
Buku Teks
Swan, John
Emond Montgomery Publications Limited, 1985
Buku Teks
Williamson, J. Peter (John Peter)
Scott, Foresman, 1968
Buku Teks
Newman, Philip C.
Frederick A. Praeger, Inc , 1956
Buku Teks