\i\c*|\c+#\c+ \i\c*|\c+#\c+ capital lowercase roman alphabet arabic roman_upper alphabet_upper normative informative normative informative left right center top middle bottom baseline left right center top middle bottom baseline internal normative informative semantic presentation normative informative normative informative normative informative normative informative normative informative compare contrast see identical modified normative informative add modify delete replace requirement recommendation permission table figure admonition formula sourcecode example note rect circle ellipse poly