Original Sources:
http://web.archive.org/web/19991003014455/http://pclt.cis.yale.edu/pclt/WINWORLD/QKREXX.HTM
http://web.archive.org/web/19991002053524/http://pclt.cis.yale.edu/pclt/WINWORLD/OS2.HTM
http://web.archive.org/web/20000303001129/http://pclt.cis.yale.edu/pclt/default.htm