Tansey, Stephen D.
Routledge, 1996
Buku Teks
Combs, James E.
Macmillan, 1984
Buku Teks
Eulau, Heinz
Bobbs-Merrill, 1963
Buku Teks
Dyke, Vernon van
Nelson, 1992
Buku Teks
Merriam, Charles E. (Charles Edward)
University of Chicago Press, 1957
Buku Teks