[1] [CITE@en[Activity Streams 2.0]] ([TIME[2017-05-21 23:50:36 +09:00]]) <https://w3c.github.io/activitystreams/core/#dfn-link>

[2] [CITE@en[Activity Vocabulary]] ([TIME[2017-05-21 23:50:36 +09:00]]) <https://w3c.github.io/activitystreams/vocabulary/#dfn-link>