Rusche, Georg
Columbia University Press, 1939
Buku Teks
Wright, Burton, author
W.B. Saunders, 1978
Buku Teks
Lucken, Karol M., author
Routledge, Taylor & Francis Group, 2017
Buku Teks
Barnes, Harry Elmer, author
Alumni, 1975
Buku Teks
Hough, Michael, author
Research Office Research and Statistics Directorate, 1998
Buku Teks