Caramani, Daniele, author
Camberidge University Press , 2004
Buku Teks
Merryman, John Henry, author
Stanford University Press, 1969
Buku Teks
Merryman, John Henry, author
Stanford University Press, 1985
Buku Teks
Freymond, Jacques, author
Frederick A. Preager, 1964
Buku Teks
British Library, 1994
Buku Referensi