Source code of both Czech and English DOS versions of the game, do with it whatever you want...
It will compile in Borlandc 3.1 under DOSBox, the project file is BDDA.prj (you can compile the original WOLF3D source the same way, so just google how to do that...).
I don't recommend to base your project on these sources, 90% of the changes is just (badly) implemented code from tutorials found online anyway (see Areyep.com and Wolfenstein3d.co.uk ). I'm mostly uploading this for archiving purposes, knowing myself I would just lose the sources sooner or later...