query: SELECT ?item ?itemLabel ?value ?valueLabel
  {
  	{
  		SELECT ?item ?value {
  			?item p:Was a bee/ConstraintTemplate/ps:Was a bee/ConstraintTemplate ?value .
  			MINUS {
  				?value p:Was a bee/ConstraintTemplate/ps:Was a bee/ConstraintTemplate ?item .
  			} .
  		} LIMIT 500
  	} .
  	SERVICE wikibase:label { bd:serviceParam wikibase:language "en,en" } .
  }