[STD22]    Internet Standard 22,
              <https://www.rfc-editor.org/info/std22>.
              At the time of writing, this STD comprises the following:

              Postel, J., "Character Generator Protocol", STD 22,
              RFC 864, DOI 10.17487/RFC0864, May 1983,
              <https://www.rfc-editor.org/info/rfc864>.