Lerner, Laurence D.
Oxford University Press, 1954
Buku Teks
Marsh, Nicholas
Higher and Further Education , 1987
Buku Teks
Drake, Henry Burgess
Oxford University Press, 1951
Buku Teks
Drake, Henry Burgess
Oxford University, 1957
Buku Teks
Chamberlain, Rudolph W.
Iroquois, 1940
Buku Teks