enhancement of packet loss-concealment of g729 standrd usin wsola.

Hi
 
I am the final year engineering student, my aim is to enhence the g729 
standard. 
Could anybody give me some relative info or give me the source code in 
C++ about time-scale modification by WSOLA, GRE  on the G 729 
strandard relative to the paper : (A Packet Loss Concealment Algorithm 
Based on Time-Scale Modification for CELP-type Speech Coders )
? Or introduce some good books in this field? thanks a lot.

Sincerely,