Flanders, Frank B., author
Delmar Cengage Learning, 2012
Buku Teks
Open Universiteit and University of Greenwich
Butterworth-Heinemann, 1993
Buku Teks
Yeates, N. T. M.
Pergamon Press, 1975
Buku Teks
Ryan Dwi Saputra, author
2016
UI - Skripsi (Membership)
Scott, John Paul, author
The University of Chicago Press, 1958
Buku Teks