Hutten, Ernest H.
Greenwood Press, 1978
Buku Teks
edited by Geoffrey Parker
Cambridge University Press, 1995
Buku Referensi
edited by Walter Gratzer
W.H.Freeman and Company, 1999
Buku Referensi
Gjertsen, Derek, author
Lilian Barber Press, 1984
Buku Referensi
edited by W.F. Bynum, E.J. Browne, Roy Porter
Macmillan Reference Books, 1989
Buku Referensi