Abbas Tashakkori, Charles Teddlie
SAGE Publications, 2010
Buku Teks
Grebanier, Bernard D.N., author
Henry Holt, 1959
Buku Teks
edited by Warren G. Bennis, Kenneth D. Benne and Robert Chin
Holt, Rinehart and Winston 1961, 1961
Buku Teks
edited by David L. Hamilton
Psychology Press, 2004
Buku Teks
Koelb, Clayton, author
Cornell University Press , 1988
Buku Teks