} else if(tag.equals(MathExpressionInlineRef.TAG)) {
express = new MathExpressionInlineRef(element,
cf.getChildContext(MathExpressionInlineRef.GROUP));
} else if(tag.equals(MathExpressionInputValueRef.TAG)) {
express = new MathExpressionInputValueRef(element,
cf.getChildContext(MathExpressionInputValueRef.GROUP));
} else if(tag.equals(MathExpressionConstValueNull.TAG)) {
express = new MathExpressionConstValueNull(element,
cf.getChildContext(MathExpressionConstValueNull.GROUP));