code: private Ref eqvOp() throws PageException {
  	Ref ref = xorOp();
  	while (cfml.forwardIfCurrent("eqv")) {
  	    cfml.removeSpace();
  	    ref = new EQV(ref, xorOp(), limited);
  	}
  	return ref;
      }
docs: Transfomiert eine Equivalence (eqv) Operation. <br />
  EBNF:<br />
  <code>xorOp {"eqv" spaces xorOp};</code>
  
  @return CFXD Element
  @throws PageException