- http://xahlee.info/emacs/emacs/elisp_syntax_coloring.html
- http://xahlee.info/emacs/emacs/elisp_font_lock_mode.html
- http://xahlee.info/emacs/emacs/elisp_syntax_table.html
- http://xahlee.info/emacs/emacs/elisp_comment_coloring.html
- http://xahlee.info/emacs/emacs/elisp_regex.html
- https://github.com/emacs-mirror/emacs/blob/master/lisp/progmodes/ruby-mode.el
- https://github.com/emacs-mirror/emacs/blob/master/lisp/progmodes/cc-awk.el
- https://github.com/typester/emacs/blob/master/lisp/obsolete/awk-mode.el