http://www.w3.org/1999/02/22-rdf-syntax-ns#first

used by 16:

• data-gov-uk-time-intervals
• geospecies
• ghent-university-academic-bibliography
• ifpri-linked-open-data-global-hunger-index
• iris2
• isocat-metadata
• land-registry-house-price-index-background-tables
• lexinfo
• lime
• mexico
• mincats
• open-library
• reference-data-gov-uk
• semantic_bible
• taxonconcept
• vivo-cu-boulder