code: func (p *Path) RegexWithRefs(pattern *regexp.Regexp) *Path {
  	return p.Filters(shape.Regexp{Re: pattern, Refs: true})
  }
docs: // RegexWithRefs is the same as Regex, but also matches IRIs and BNodes.
  //
  // Consider using it carefully. In most cases it's better to reconsider
  // your graph structure instead of relying on slow unoptimizable regexp.
  //
  // An example of incorrect usage is to match IRIs:
  // 	<http://example.org/page>
  // 	<http://example.org/page/foo>
  // Via regexp like:
  //	http://example.org/page.*
  //
  // The right way is to explicitly link graph nodes and query them by this relation:
  // 	<http://example.org/page/foo> <type> <http://example.org/page>