Jones, Leo
Let's talk 1 : Teacher's manual
Cambridge University Press , 2011
 Buku Teks SO
Jones, Leo
Let's talk 3: teacher's manual / Leo Jones
Cambridge University Press, 2008
 Buku Teks SO
Jones, Leo
Let's talk 3
Cambridge University Press, 2011
 Buku Teks SO
Jones, Leo
Let's talk 3 : self-study audio CD
Cambridge University Press, 2008
 Multimedia
Gordon, Morton J.
A manual for speech improvement / Morton J. Gordon and Helene H. Wong
Prentice-Hall, 1961
 Buku Teks SO