[1] RDF Schema 1.1 ( (2/27/2014, 12:42:23 PM 版)) <https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-schema/index.html#h3_ch_label>
[2] Web Annotation Vocabulary (2/23/2017, 5:14:26 PM) <https://w3c.github.io/web-annotation/vocab/wd/#rdfs-label>
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