From the MH READ_ME file:

     Although the MH system was originally developed by the RAND
     Corporation, and is now in the public domain, the RAND Cor-
     poration assumes no responsibility for MH or this particular
     modification of MH.

     In addition, the Regents of the University of California
     issue the following disclaimer in regard to the UCI version
     of MH:
          "Although each program has been tested by its contribu-
          tor, no warranty, express or implied, is made by the
          contributor or the University of California, as to the
          accuracy and functioning of the program and related
          program material, nor shall the fact of distribution
          constitute any such warranty, and no responsibility is
          assumed by the contributor or the University of Cali-
          fornia in connection herewith."

     This version of MH is in the public domain, and as such,
     there are no real restrictions on its use.  The MH source
     code and documentation have no licensing restrictions what-
     soever.  As a courtesy, the authors ask only that you pro-
     vide appropriate credit to the RAND Corporation and the
     University of California for having developed the software.
