code: private void addChildElements() {
  		for (Node node : nodes) {
  			Collection<? extends Node> childNodes = helper.getChildNodes(node);
  			for (Node child : childNodes)
  				if (matchTag(child))
  					result.add(child);
  		}
  	}
docs: Add child elements.
  
  @see <a href="http://www.w3.org/TR/css3-selectors/#child-combinators">Child combinators</a>