Bone, Hugh A.
University of Washington Press, 1958
Buku Teks
Sorauf
Little, Brown and Company, 1980
Buku Teks
Burns, James McGregor
Prentice-Hall, 1963
Buku Teks
Bone, Hugh A.
McGraw-Hill, 1965
Buku Teks
Sorauf, Frank J.
Little, Brown & Co., 1988
Buku Teks