Silver and gold coin coins after 337 CE

silver-gold.sparql

PREFIX crm: <http://www.cidoc-crm.org/cidoc-crm/>
PREFIX dcmitype: <http://purl.org/dc/dcmitype/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>
PREFIX nm: <http://nomisma.org/id/>
PREFIX nmo: <http://nomisma.org/ontology#>
PREFIX org: <http://www.w3.org/ns/org#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

SELECT ?authority (min(?start) as ?date) ?material (count(?coin) as ?count) WHERE {
  ?type dcterms:source nm:ric ;
        a nmo:TypeSeriesItem ;
        nmo:hasAuthority ?authority ;
        nmo:hasStartDate ?start FILTER (?start >= "0337"^^xsd:gYear).   
  {?type nmo:hasMaterial nm:av }
  UNION {?type nmo:hasMaterial nm:ar }
  ?type nmo:hasMaterial ?material
  FILTER NOT EXISTS {?type skos:broader ?parent}
  ?coin nmo:hasTypeSeriesItem|nmo:hasTypeSeriesItem/skos:broader+ ?type .
} GROUP BY ?authority ?date ?material ORDER BY ?date ?authority ?material