数字字符参引
numeric character reference
内容参引属性
content reference attribute
content reference
明确内容参引
explicit content reference
简短参引使用宣告
short reference use declaration
简短参引定界符角色
short reference delimiter role
简短参引定界符
short reference delimiter
语法参引字符集
syntax-reference character set
附名的字符参引
named character reference
参引具体语法
reference concrete syntax