The CGNS software is available free of charge, under the terms of the CGNS License, from http://www.cgns.org . Also available there are the cgnstools utilities, the source code examples from A User's Guide to CGNS, and additional Fortran source code examples.
The CGNS Library contains source code for the Mid-Level Library, the CGIO core, and the ADF and HDF5 implementations, plus CMake and configure scripts for building the library for a variety of platforms.
The CGNS documentation may be accessed via the CGNS Documentation home page. In addition to current version, documentation may also be available for the previous and beta versions of CGNS. All the CGNS documentation is available in HTML form (PDF is no longer being supported except for the SIDS).
In addition to the CGNS documentation itself, several conference papers and slide presentations are available, as well as minutes from the CGNS meetings and telecons.