Ur, Penny
Cambridge University Press, 1999
Buku Referensi
Potapova, Nina F.
Foreign Languages Publishing House, 1959
Buku Teks SO
T. S. Lie
Angus and Robertson, 1996
Buku Teks SO
translated into modern Chinese by Chen Junying and Jianyuan
Hunan People Publishing House, 2008
Buku Teks
Book House Training Centre/Unesco
Book House Training Centre, 1991
Buku Referensi