[BCP19]    Best Current Practice 19,
              <https://www.rfc-editor.org/info/bcp19>.
              At the time of writing, this BCP comprises the following:

              Freed, N. and J. Postel, "IANA Charset Registration
              Procedures", BCP 19, RFC 2978, DOI 10.17487/RFC2978,
              October 2000, <https://www.rfc-editor.org/info/rfc2978>.