* [http://perforce.openwatcom.org:4000/@md=d&cd=//depot/public/&c=TNZ@//depot/public/4os2/?ac=83 Perforce repository] - Web interface to the 4os2 perforce source code repository * [http://toogam.com/software/archive/usrintrf/jpsoft/jpsoft.htm Toogam] - Info about 4os2 history at toogam.com * [http://www.4dos.info/v4os2.htm 4OS2 Versions] - 4os2 history by Klaus Meinhard