edited by Astrik L. Gabriel
Mediaeval Institute, University of Notre Dame, 1974
Buku Teks
Phillips, Estelle M, author
Open University Press, 2005
Buku Teks
Phillips, Estelle M.
Open University Press, 1994
Buku Teks
David Rusman
Jossy-Bass, 1980
Buku Teks
McCorkle, Chester O., author
Jossey-Bass Publishers, 1982
Buku Teks