This member of Knowledge Representation Systems, developed by David E. Young, is currently in Production stage; version 3.2 was released 17 September 2007. LISA is distributed under the terms of the LGPL. The project resides at http://lisa.sourceforge.net.
Note: As of December 2008, the sourceforge repository doesn't seem get updated regulary. A version incorporating all current patches can be found here. To clone the repository, use
git clone http://git.moltkeplatz.de/lisa.git