Keith, Lyman A.
McGraw-Hill, 1975
Buku Teks SO
Paulson, Edward
Prenada Media, 2003
Buku Teks SO
Griffin, Ricky W.
Prentice-Hall, 1999
Buku Teks
Griffin, Ricky W.
Prentice-Hall, 2002
Buku Teks
Wheeler, Bayard O.
Harper & Row. Publisher, 1968
Buku Teks