[BCP160]   Best Current Practice 160,
              <https://www.rfc-editor.org/info/bcp160>.
              At the time of writing, this BCP comprises the following:

              Barnes, R., Lepinski, M., Cooper, A., Morris, J.,
              Tschofenig, H., and H. Schulzrinne, "An Architecture for
              Location and Location Privacy in Internet Applications",
              BCP 160, RFC 6280, DOI 10.17487/RFC6280, July 2011,
              <https://www.rfc-editor.org/info/rfc6280>.