code: public AbcNode getChild(String label) {
  		if (label == null || label.equals(""))
  			return null;
  		String[] generation = label.split("/");
  		String child = generation[0];
  		String grandchild = "";
  		if (generation.length > 1) {
  			for (int i = 1; i < generation.length; i++) {
  				grandchild += (grandchild.equals("") ? "" : "/");
  				grandchild += generation[i];
  			}
  		}
  		Iterator it = childs.iterator();
  		while (it.hasNext()) {
  			AbcNode abcn = (AbcNode) it.next();
  			if (child.equals(abcn.getLabel())) {
  				if (grandchild.equals(""))
  					return abcn;
  				else
  					return abcn.getChild(grandchild);
  			}
  		}
  		return null;
  	}
docs: Returns the first child having the request label, <code>null</code> if
  doesn't exist.
  <p>
  Can get directly a grandchild if label contains <tt>/</tt> e.g.
  abcHeader.getChild("FieldNumber/DIGITS") returns the grandchild "DIGITS"
  if exist in FieldNumber child.
  
  @param label One of {@link AbcTokens} constants