@prefix skos:	<http://www.w3.org/2004/02/skos/core#> .
@prefix isac:	<http://webisa.webdatacommons.org/concept/> .
isac:_father_	skos:broader	isac:_mapmaker_ .
isac:_map_	skos:broader	isac:_mapmaker_ .
isac:_year_	skos:broader	isac:_mapmaker_ .
isac:_clark_	skos:broader	isac:_mapmaker_ .
isac:_mercator_	skos:broader	isac:_mapmaker_ .