Mcinnes, Graham
Toronto The Macmillan Co of Canada Limited 1950
Buku Teks
University of Toronto Press, 2014
Buku Teks
edited by Jack Davis and Robert Lecker
General Publishing, 1982
Buku Teks
Barbeau, Joseph E.
Custom book program of northeastern University , 1985
Buku Teks
Ackerman, Joseph
Washington, D>C. Resources for the Future c. 1961,
Buku Teks