The following special-character words are not underlined in general
  formats but are required where they appear:

      colon      (:)            single (=) and double (==) equal signs

      period     (.)            left (() or right ()) parenthesis

      plus sign  (+)            left (<) or right (>) angle bracket

      minus sign (-)            single (*) and double (**) asterisk

      slash      (/)