Lower, Arthur R.M.
Longmans, Green and Company, 1958
Buku Teks
Lower, Arthur R.M.
The Ryerson Press, 1952
Buku Teks
Wagener, Albert M.
D. Van Nostrand Company, Inc., 1950
Buku Teks
Siegel, Arthur
McGraw-Hill Ryerson, 1983
Buku Teks
Keenleyside, Hugh Ll.
Alfred A. Knopf , 1952
Buku Teks