Wilson, Steve D.
Burgess, 1967
Buku Teks
edited by R. Barer and V.E. Cosslett
Academic Press, 1984
Buku Teks
Watt, Ian M.
Cambridge University Press, 1997
Buku Teks
Williams, David B.
Plenum Press, 1996
Buku Teks
Wallis, T. E.
Little, Brown, 1965
Buku Teks