Sting

[Voralphion]

Sting was a long dagger, the companion of Glamdring and Orcrist (as was Angrist to Anglachel)

Where does it say that sting was the companion of Glamdring and Orcrist, aside from all being made in Gondolin and being in the same troll hoard, I didn't think they had anything in common.
Also, I don't think Angrist was the companion of Anglachel since they were made by different people, (Angrist by Telchar, Anglachel by Eol) and they were borne by different people, (Angrist by Curufin then Beren, Anglachel by Beleg then Turin)