Oxley, Harold
Gunung Mulia, 1993
Buku Teks
Sills, Theodore R
Richard D.Irwin,Inc, 1951
Buku Teks
Seitel, Fraser P.
Prentice-Hall, 1998
Buku Teks
Jefkins, Frank William, author
Erlangga, 1996
Buku Teks
Jefkins, Frank William, author
Erlangga, 1996
Buku Teks