edited by Geoffrey Barraclough
Times Books, 1984
Buku Referensi
Published for Newsweek by Funk & Wagnalls, 1950
Buku Teks
Turnbull, C. M. (Constance Mary)
Oxford University Press, 1985
Buku Teks
Powell, Robert
Periplus, 2004
Buku Teks
Vinacke, Harold M.
Appleton-Century-Crofts, 1950
Buku Teks