The main author of libsndfile is Erik de Castro Lopo <erikd@zip.com.au>.

The code in the src/GSM610 directory was written by Jutta Degener 
<jutta@cs.tu-berlin.de> and Carsten Bormann <cabo@cs.tu-berlin.de>.
They should not be contacted in relation to libsndfile or the GSM 6.10 code 
that is part of libsndfile. Their original code can be found at:

    http://kbs.cs.tu-berlin.de/~jutta/toast.html

Code in the src/G72x directory was released by Sun Microsystems, Inc. to the 
public domain. Minor modifications were required to integrate these files 
into libsndfile. The changes are listed in src/G72x/ChangeLog.