Macmillan, 1972
Buku Teks
Toennies, Ferdinand
The University of Chicago Press, 1971
Buku Teks
Vincenzo Costigliola, editor
[, Springer], 2012
eBooks
edited by Rosalind S. Miller, and Helen Rehr
Prentice-Hall, 1983
Buku Teks
Praeger Publ., 1982
Buku Teks