query: #A PLB (or better: the main entrance of the PLB) can be only on one street, so P669 can have only one value
  #Public library branches - are they in the correct street and is that street in the correct location & municipality?
  #I.e. check that the street the PLB lies on (P669), is situated in the correct location (P276) and municipality (P131) (via the WD-descriptions of street , location and municipality) 
  
  SELECT DISTINCT 
  ?item ?itemLabel
  #A PLB (or better: the main entrance of the PLB) can be only on one street, so P669 can have only one value
  (GROUP_CONCAT(DISTINCT ?streetLabel ; separator = " XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX ") as ?Straat)
  (GROUP_CONCAT(DISTINCT ?streetDescription ; separator = " XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX ") as ?StraatBeschrijving) 
  ?locationLabel ?locationDescription
  ?municipalityLabel ?municipalityDescription
  #?municipalityCheckLabel
  
  WHERE
    {
    ?item (p:P31/ps:P31) wd:Q28564,wd:Q11396180;wdt:P17 wd:Q55. 
    OPTIONAL {?item p:P669 [ps:P669 ?street].}    
    OPTIONAL{?item wdt:P276 ?location.}
    OPTIONAL{?item wdt:P131 ?municipality.}
  # ?location wdt:P131 ?municipalityCheck.  
  
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". 
                            ?item rdfs:label ?itemLabel.
                            ?street rdfs:label ?streetLabel.
                            ?street schema:description ?streetDescription.
                            ?location rdfs:label ?locationLabel.
                            ?location schema:description ?locationDescription.
                            ?municipality rdfs:label ?municipalityLabel.
                            ?municipality schema:description ?municipalityDescription.
                           }  
  }
  
  GROUP BY ?item ?itemLabel ?locationLabel ?locationDescription ?municipalityLabel ?municipalityDescription
  ORDER BY DESC(?item)
  #LIMIT 10