@prefix skos:	<http://www.w3.org/2004/02/skos/core#> .
@prefix isac:	<http://webisa.webdatacommons.org/concept/> .
isac:_day_	skos:broader	isac:time_reference_ .
isac:_date_	skos:broader	isac:time_reference_ .
isac:_year_	skos:broader	isac:time_reference_ .
isac:_gp_	skos:broader	isac:time_reference_ .