[BCP183]   Best Current Practice 183,
              <https://www.rfc-editor.org/info/bcp183>.
              At the time of writing, this BCP comprises the following:

              Saint-Andre, P., "A Uniform Resource Name (URN) Namespace
              for Examples", BCP 183, RFC 6963, DOI 10.17487/RFC6963,
              May 2013, <https://www.rfc-editor.org/info/rfc6963>.