Special Characters to Escape
Special characters must be escaped only if they have special meaning in the context in which they are being used. For example, the asterisk (*) is a special character only in the "Include" and "Exclude" attributes of an item definition, or in a call to CreateItem. In all other cases, the asterisk is treated as a literal asterisk. While you do not need to escape asterisks everywhere in project files, doing so does no harm.
The full list of special characters to escape follows:
Percent sign, used to reference metadata.
Dollar sign, used to reference properties.
At sign, used to reference item lists.
Open parenthesis, used in lists.
Close parenthesis, used in lists.
Apostrophe (or tick mark), used in conditions and other expressions.
Semicolon, a list separator.
Question mark, a wildcard character when describing a file spec in an item's Include/Exclude section.
Asterisk, a wildcard character when describing a file spec in an item's Include/Exclude section.