[STD40]    Internet Standard 40,
              <https://www.rfc-editor.org/info/std40>.
              At the time of writing, this STD comprises the following:

              Laboratories, B. B. A. N., "Host Access Protocol
              specification", STD 40, RFC 907, DOI 10.17487/RFC0907,
              July 1984, <https://www.rfc-editor.org/info/rfc907>.