code: public int compareTo(PageRef o) {
  		int diff = bookRef.compareTo(o.bookRef);
  		if(diff != 0) return diff;
  		return getPath().compareTo(o.getPath());
  	}
docs: Ordered by bookRef, path.
  
  @see  BookRef#compareTo(com.semanticcms.core.model.BookRef)
  @see  #getPath()