MZ Associates Ltd has ceased trading.
Mark Zytynski, the author of the packages SID and STABLE
will continue to support these systems on an informal basis.
SID and STABLE are available for download
free of charge from this site. These are unlicensed and
unsupported versions which can be freely copied and distributed.
STABLE - Slope Stability
Analysis System

Details here.....
SID - Geotechnical Data Management
System

Details here.....