Stanza 13: When Freyja is told she must marry the giant Þrymr, she becomes so enraged that the great torc of the Brísingar breaks apart from the force of her fury.
Freyja became incensed then and snorted,
at which all the hall of the Æsir shook;
the great torc of the Brísingar fractured:
‘You’d know me to be most man-eager,
if I drive with you into Jǫtunheimar!’
Stanza 15: Heimdallr suggests that Þórr should be disguised as Freyja to retrieve the hammer, and that the disguise must include the Brísingamen.
‘Let’s bind Þórr, then, in a bride’s linen,
let him have the great torc of the Brísingar!
Stanza 19: As they dress Þórr in his bridal disguise, the gods place the Brísingamen upon him.
Then they bound Þórr in a bride’s linen
and the great torc of the Brísingar;
they had keys clanging at his belt,
and women’s skirts falling round his knees,
and on his breast broad jewels,
and they topped it off tidily about his head!
Chapter 35(p. 30): In the description of the goddess Freyja and her various names and possessions, the necklace is named as belonging to her.
Freyia owned the Brisings’ necklace.
Chapter 8-16(p. 76): When listing the kennings (poetic names) for Heimdall, he is called the "recoverer of Freyia’s necklace." The text also notes the occasion when he fought Loki for it.
How shall Heimdall be referred to? By calling him... recoverer of Freyia’s necklace... on that occasion he contended with Loki for the Brisingamen.
Chapter 16(p. 76): In the list of kennings for Loki, he is identified as the "thief from giants, of goat and Brisingamen and Idunn’s apples."
How shall Loki be referred to? By calling him son of Farbauti and Laufey, of Nal, […] Geirrod’s visitor and casket-ornament, thief from giants, of goat and Brisingamen and Idunn’s apples, relative of Sleipnir
Chapter 16-17(p. 77): A verse by the skald Úlfr Uggason is quoted, which refers to the conflict between Heimdall and Loki over the necklace.
Renowned defender [Heimdall]... is first to get hold of the beautiful sea-kidney [jewel, Brisingamen].
Chapter 18-22(p. 86): This is the reference I missed. In the list of proper kennings for Freyja, being the owner of the necklace is explicitly mentioned.
How shall Freyja be referred to? By calling her daughter of Niord, sister of Freyr, wife of Od, mother of Hnoss, possessor of the fallen slain and of Sessrumnir and tom-cats, of Brisingamen, Van-deity, Van-lady, fair-tear deity.
Chapter 22(p. 87): In the poem Haustlöng, Loki is referred to by the kenning "thief of Brising’s girdle [Brisingamen]."
The thief of Brising’s girdle [Brisingamen] afterwards caused the gods’ lady [Idunn] to go into the rock-Nidud’s [giant’s] courts...