The file MIX.DOC, as well as the samples in elevator.mixal and mistery.mixal
are a contribution from Eric S. Raymond's MIXAL.  They contain the actual
text of TAOCP vol 1 describing MIXAL and two verbatim programs from the book.
Donald Knuth and Addison Wesley granted Eric permission for distributing the
under the following terms, which we inherit:

The source code in prime.mix, mystery.mix, and elevator.mix and the
text in MIX.DOC are excerpted from "The Art Of Computer Programming".
Addison-Wesley and Donald Knuth have specifically granted permission
for this material and all other MIX code examples from that book to be
distributed in conjunction with any open-source implementation of MIX
under the license(s) applying to that implementation.