You can refer to Unicode code pages by name too.
Two forms:
\p{IsXXX} - any character from the code page 'XXX'
\P{IsXXX} - any character not from the code page 'XXX'
Example:
\p{IsGreek} - any greek character
\P{IsMathematicalOperators} - any non-math operator character.
See page 190-195 for more information.