Judd, Charles M.
Methuen, 1991
Buku Teks
Sjoberg, Gideon
Harper & Row Publishers, 1968
Buku Teks
Lee, Raymond M.
Open University Press, 2000
Buku Teks
Babbie, Earl R.
Cengage Learning, 2016
Buku Teks
by Claire Selltiz ... [and others]
Methuen, 1965
Buku Teks