Ahmed, Ash, author
Routledge, 2015
Buku Teks
Van Vlack, Lawrence H., author
Addison-Wesley, 1980
Buku Teks
John, V.B., author
Macmillan, 1983
Buku Teks
John, V.B., author
Macmillan, 1977
Buku Teks
John, Vernon, author
Macmillan, [Date of publication not identified]
Buku Teks