# MDL_Primer_and_Manual.pdf MDL Primer and Manual (1977) by Stu Galley and Greg Pfister. This documents the MDL interpreter version 54 (ITS) and version 104 (TENEX), and is an earlier version of "The MDL Programming Language" document that is also here. # MDL_Programming_Environment.pdf The MDL Programming Environment (1980), by David Lebling. # MDL_Programming_Language.pdf The MDL Programming Language (1979), by Stu Galley and Greg Pfister. This documents the MDL interpreter version 55 (ITS) and version 105 (TENEX and TOPS-20). # MDL_Programming_Primer.pdf The MDL Programming Language Primer (1980), by Michael Dornbrook and Marc Blank.