The differences between sbmf13.zip and sbmf13a.zip are (1) the
inclusion of this file; (2) updating of plain.mf and modes.mf;
(3) use of info-zip for archiving; (4) minor editing of sbmf13.doc.
To unpack this file to the correct directories,
place the zip file in the root directory,
make the root the default, and execute
         unzip sbmf13a
Then consult the DOC file in \MF for further details.
