Enkvist, Nils Erik
Mouton, 1973
Buku Teks SO
Simpson, Paul
Routledge , 2004
Buku Teks
edited by Braj B. Kachru and Herbert F.W. Stahlke
Linguistic Research, 1972
Buku Teks SO
Simpson, Paul
Routledge , 2004
Buku Teks SO
edited by Michael Toolan
Routledge, 1992
Buku Teks SO