PREFIX sdmx-attribute: PREFIX vann: PREFIX sdmx-concept: PREFIX skos: PREFIX sh: PREFIX xsd: PREFIX qb: PREFIX lso: PREFIX owl: PREFIX sdmx: PREFIX rdfs: PREFIX dc: PREFIX dbr: PREFIX rdf: PREFIX dct: PREFIX dbo: PREFIX lsi: PREFIX ov: PREFIX dcmit: PREFIX sdmx-dimension: PREFIX ls: lso:refDate a qb:DimensionProperty, rdf:Property; lso:completeness "1.0"^^xsd:double; rdfs:comment "the date an observation refers to"; rdfs:domain qb:Observation; rdfs:label "reference date"; rdfs:range xsd:date; rdfs:subPropertyOf sdmx-concept:refPeriod.