code: public static Ref createTagRef(String name) {
      CheckUtilities.checkStringArgument(name, "name");
  
      Ref cn = new Ref();
      cn.refType = RefType.TAG;
      cn.name = name;
      return cn;
    }
docs: Creates a <code>Ref</code> of type <code>TAG</code>.
  
  @param name
  The tag name of this ref. If the value is null, a <code>NullPointerException</code>
  is thrown. If the value has length zero, an <code>IllegalArgumentException</code> is
  thrown.
  @return A <code>Ref</code> instance of type <code>TAG</code>.