[BCP170]   Best Current Practice 170,
              <https://www.rfc-editor.org/info/bcp170>.
              At the time of writing, this BCP comprises the following:

              Clark, A. and B. Claise, "Guidelines for Considering New
              Performance Metric Development", BCP 170, RFC 6390,
              DOI 10.17487/RFC6390, October 2011,
              <https://www.rfc-editor.org/info/rfc6390>.