Ellis, Rob
Blackwell, 1990
Buku Teks
Leaver, Betty Lou
Cambridge Press , 2005
Buku Teks SO
edited by Eric Kellerman and Michael Sharwood Smith
Pergamon, 1986
Buku Teks SO
Bloomfield, Leonard
Holt, Rinehart and Winston, 1961
Buku Teks SO
edited by Jessica Williams and Bill Van Patten
NY : Routledge, 2015
Buku Teks SO