Higgins, Hugh, author
Heinemann Educational, 1975
Buku Teks
Thiessen, Frank J.
Prentice-Hall, 1997
Buku Teks
Teweles, Richard J.
McGraw-Hill Book , 1987
Buku Teks
Institute of southeast Asian studies, 1996
Buku Teks
Thomas, Frank N, author
Springer, 2013
Buku Teks