Johnson, Earl S., author
Macmillan, 1956
Buku Teks
Kahn, Alfred J., author
Russel Sage Foundation, 1969
Buku Teks
Midgley, James, author
Sage, 2014
Buku Teks
Smalley, Ruth Elizabeth, author
Columbia University Press, 1971
Buku Teks
edited by R. Meurig Evans
Macmillan, 1975
Buku Teks