Arntz, Helmut
The Press and Information Office of the federal Germa Govermant, [1967]
Buku Teks
Kitchen, Martin
Blackwell Pub, 2012
Buku Teks
Barraclough, Geoffrey, 1908-1984
Basil Blackwell, 1952
Buku Teks
Conant, James B.
Harvard University Press, 1958
Buku Teks
Snyder, Louis L.
Van Nostrand Reinhold, 1957
Buku Teks