Alexander Hamilton Institute , 1955; 1961
Buku Teks
Saunders, N.F.T. (Norman Frank Tilbury), author
Sir Isaac Pitman & Sons, 1946
Buku Teks
Amrine, Harold T., author
Prentice-Hall, 1975
Buku Teks
by Harold T. Amrine [and others]
Prentice-Hall, 1993
Buku Teks
Davis, Ralph Currier.
Harper & Row, 1940
Buku Teks
Knowles, Asa S., author
Macmillan, 1946
Buku Teks