diff --git a/Classes/PHPExcel/Calculation.php b/Classes/PHPExcel/Calculation.php
index 0478b05d..60dca6ef 100644
--- a/Classes/PHPExcel/Calculation.php
+++ b/Classes/PHPExcel/Calculation.php
@@ -40,9 +40,9 @@ if (!defined('CALCULATION_REGEXP_CELLREF')) {
 	//	Test for support of \P (multibyte options) in PCRE
 	if(defined('PREG_BAD_UTF8_ERROR')) {
 		//	Cell reference (cell or range of cells, with or without a sheet reference)
-		define('CALCULATION_REGEXP_CELLREF','((([^,!]*)|(\'[^\']*\')|(\"[^\"]*\"))!)?\$?([a-z]{1,3})\$?(\d+)');
+		define('CALCULATION_REGEXP_CELLREF','((([^\s,!&%^\/\*\+<>=-]*)|(\'[^\']*\')|(\"[^\"]*\"))!)?\$?([a-z]{1,3})\$?(\d{1,7})');
 		//	Named Range of cells
-		define('CALCULATION_REGEXP_NAMEDRANGE','((([^,!]*)|(\'[^\']*\')|(\"[^\"]*\"))!)?([_A-Z][_A-Z0-9]*)');
+		define('CALCULATION_REGEXP_NAMEDRANGE','((([^\s,!&%^\/\*\+<>=-]*)|(\'[^\']*\')|(\"[^\"]*\"))!)?([_A-Z][_A-Z0-9]*)');
 	} else {
 		//	Cell reference (cell or range of cells, with or without a sheet reference)
 		define('CALCULATION_REGEXP_CELLREF','(((\w*)|(\'[^\']*\')|(\"[^\"]*\"))!)?\$?([a-z]{1,3})\$?(\d+)');