Hengeveld, R.
Cambridge University Press, 1990
Buku Teks
edited by Samuel Sipp
McGraw-Hill , 1982
Buku Teks
Nolan, Mary, author
Bailliere Tindall, 1998
Buku Teks
Ruth, Matthias, author
Springer, 1997
Buku Teks
Pesaran, M.H., author
Ellis Horwood , 1980
Buku Teks