[1] 絶対Absolute URI 参照reference := 絶対URI [ "#" 素片識別子 ]

[2] XML/URI Questions and Answers () https://www.w3.org/2000/06/uriqa3934.html

Unfortunately, the URI specification does not have a term for 'an absolute URI with an optional fragment identifier'. For the purpose of this discussion, let's call that a URI+.