Fortran source code of the MOID calculating program (with comments)
MOID.F (.F file ~10kB)

The paper containing complete description of idea and methods used in MOID calculating program
T.Wiśniowski and H.Rickman, “A Fast, Geometric Method for Calculating Accurate Minimum Orbit Intersection Distances (MOIDs)” 2013 Acta Astronomica - (PDF file ~600kB)

Link to actual and complete Minor Planet Center asteroids database, updated daily
http://www.minorplanetcenter.org/iau/MPCORB/MPCORB.DAT

Packed database of numbered asteroids, downloaded on March 8th, 2013 from Minor Planet Center and used on this website for calculations (only for compare)
MPN.ZIP (ZIP file ~22MB)