English Universities Press, 1955
Buku Referensi
Girard, Denis
Cassell , 1981
Buku Referensi
Surenne, Gabriel
Oliver and Boyd, [date of publication not identified]
Buku Referensi
Urwin, Kenneth
Hodder & Stoughton, 1968
Buku Referensi
edited by Marianne Chalmers and Martine Pierquin
Oxford University Press, 2002
Buku Referensi