University League for Social Reform; edited by Peter Russell
McGraw-Hill, 1966
Buku Teks
Backing, Richard C
James Lewis ,
Buku Teks
by Jack Bavington
Maclean-Hunter Learning Materials, 1976
Buku Teks
edited by John Robert Colombo
Hurtig Publishers, 1978
Buku Teks
Creighton, Donald, author
Macmillan, 1959
Buku Teks