http://www.aktors.org/ontology/portal#has-volume

used by 12:

• rkb-explorer-budapest
• rkb-explorer-deepblue
• rkb-explorer-deploy
• rkb-explorer-ft
• rkb-explorer-ibm
• rkb-explorer-irit
• rkb-explorer-laas
• rkb-explorer-newcastle
• rkb-explorer-pisa
• rkb-explorer-risks
• rkb-explorer-roma
• rkb-explorer-ulm