http://digilab.ptb.de/vocab/http://digilab.ptb.de/vocab/skos/66327initial intrinsic error http://digilab.ptb.de/vocab/skos/66327 Construction and operation of measuring instruments BT http://digilab.ptb.de/vocab/skos/66327 durability error RT http://digilab.ptb.de/vocab/skos/66327 performance test RT http://digilab.ptb.de/vocab/skos/66327 durability RT http://digilab.ptb.de/vocab/skos/66327 measuring instrument RT http://digilab.ptb.de/vocab/skos/66327 intrinsic error RT