Documentation, including standards and proposals

lang/scheme/doc/

   bib/       Bibliographies related to Scheme.
   intro/     Introductions, tutorials, and quick reference 
              guides for Scheme.
   macros/    Proposals and implementations for macros in 
              Scheme.
   notes/     Summaries and interesting notes about 
              Scheme-related stuff.
   standard/  Scheme standards documents and test suites