query: SELECT ?item ?itemLabel ?date ?approvalLabel ?ref_url
  WHERE 
  {
    ?item p:P1435 ?thing.
    ?thing ps:P1435 wd:Q18342392.
    optional {?thing pqv:P580 ?datez. ?datez wikibase:timeValue ?date.} 
    optional {?thing pq:P790 ?approval}
    optional {?thing prov:wasDerivedFrom ?ref. ?ref pr:P854 ?ref_url.}
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }