Zsiga, Elizabeth C.
West Sussex Wiley-Blackwell, 2013
Buku Teks SO
Wise, Claude Merton
Prentice-Hall, 1957
Buku Teks SO
edited by Bruce Hayes, Robert Kirchner, and Donca Steriade
Cambridge University Press, 2004
eBooks
Lass, Roger
IKIP Semarang Press , 1984
Buku Teks SO
Odden, David
Cambridge Press, 2007
Buku Teks SO