Andrews, Frank M.
University of Michigan, 1981
Buku Teks
edited by Alan Bryman, Robert G. Burgess
Routledge , 1995
Buku Teks
Markus, Gregory B.
Sage, 1979
Buku Teks
Barnett, Vic
John Wiley & Sons, 1978
Buku Teks
by M.J. Crowder ... [et al.]
Chapman & Hall, 1991
Buku Teks