public String getExpressionString()
	{
		if( ((expression == null) || (expression.size() == 0)) && (getCachedOOXMLExpression() != null) )
		{
			return "=" + getCachedOOXMLExpression();
		}
		if( expression != null )
		{
			return FormulaParser.getExpressionString( expression );
		}
		return "=";
	}