Distinct subjects for predicate ns4:hardheid sorted by frequency

Resource	Count
Antimoon	2
Bismut	2
Calcium	2
Goud	2
IJzer (element)	2
Nikkel	2
Tin (element)	2
Titanium	2
Aluminium	1
Diamant	1
Gips	1
Kwik	1
Natrium	1
Platina	1
Telluur	1