Anderson, William, 1888-
Holt, Rinehart and Winston, 1954
Buku Teks SO
MacDonald, Austin F.
Thomas Y. Crowell , 1951
Buku Teks
Agger, Robert E.
N.Y. John-Wiley , 1966
Buku Teks SO
Adrian, Charles R.
McGraw-Hill, 1977
Buku Teks
Adrian, Charles R.
McGraw-Hill, 1955
Buku Teks