[BCP60]    Best Current Practice 60,
              <https://www.rfc-editor.org/info/bcp60>.
              At the time of writing, this BCP comprises the following:

              Floyd, S., "Inappropriate TCP Resets Considered Harmful",
              BCP 60, RFC 3360, DOI 10.17487/RFC3360, August 2002,
              <https://www.rfc-editor.org/info/rfc3360>.