Kempson, Ruth M., author
Blackwell , 2001
Buku Teks
Allen, James, author
The Benjamin Cumming Pub. Co., 1987
Buku Teks SO
Schobeiri, Meinhard T., author
[, Springer], 2012
eBooks
J. Joel Carrillo R., M. Adrian Ortega G., editor
Taylor and Francis, 2008
Buku Teks
North Holland, 1988
Buku Teks