[1] XQuery 3.1: An XML Query Language (2017-03-20 09:23:33 +09:00) https://www.w3.org/TR/2017/REC-xquery-31-20170321/#id-static-decimal-format-exponent-separator
[2] XML Path Language (XPath) 3.1 (2017-03-20 09:18:04 +09:00) https://www.w3.org/TR/2017/REC-xpath-31-20170321/#id-static-decimal-format-exponent-separator
[3] Musa