Hagopain, Mark N.
Longman, 1978
Buku Teks
Conlin Joseph R
The Glencoe Press, 1968
Buku Teks
Jürgen R. Grote and Claudius Wagemann, editors
Routledge, Taylor & Francis Group, 2019
Buku Teks
edited by Meredith L. Weiss and Saliha Hassan
Routledge, 2003
Buku Teks
Blau, Joseph L., author
Prentice-Hall, 1965
Buku Teks