Lass, Roger
IKIP Semarang Press , 1984
Buku Teks
Cambridge University Press, 2002
eBooks
edited by John A. Goldsmith
Blackwell , 1999
Buku Teks SO
Gussmann, Edmund
Cambridge University Press, 2002
Buku Teks SO
edited by John A. Goldsmith, Jason Riggle, Alan Yu
Wiely-Blackwell, 2011
Buku Teks