Levitan, Sar A., author
Harper & Row, 1982
Buku Teks
edited by Solomon W. Polachek, Konstantinos Pouliakas, Giovanni Russo, Konstantinos Tatsiramos
Emerald, 2017
eBooks
Wolfbein, Seymur L.
Science Research Assicuates, 1964
Buku Teks
edited by Arthur M. Ross
University of California Press, 1965
Buku Teks
Jackson, Grdon E., author
Prentice-Hall, 1993
Buku Referensi