edited by Judith B. Balderston and Frederick E. Balderston
University of California, 1993
Buku Teks
Vught, Frans A. van
Springer, 2012
eBooks
UNESCO, 1978
Buku Teks
Her Majesty's Stationery Office, 1987
Buku Teks
edited by Maria Slowey, David Watson
Open University Press, 2003
Buku Teks