public  REXSubClassOfImpl getREXSubClassOf(
			REXClassExpressionImpl lhs, REXClassExpressionImpl rhs) {
		// TODO Auto-generated method stub
		REXSubClassOfImpl axiom = null;
		if(rhs instanceof REXObjectSomeValuesFromImpl)
		{
			REXObjectSomeValuesFromImpl some = (REXObjectSomeValuesFromImpl) rhs;
			REXObjectPropertyExpressionImpl role = some.getProperty();
			REXClassExpressionImpl filler = some.getFiller();
			axiom = getREXSubClassOfSomeValuesFrom(lhs, role, filler);
			axiom.link = true;
		}
		else
		{
			lhs.subAxioms.putIfAbsent(rhs, new REXSubClassOfImpl(lhs, rhs));
			axiom = lhs.subAxioms.get(rhs);
		}

		return axiom;
	}