This might be just a supplemental entry adding to an entry in the Main Volume.
á-birgan
.Add to á-byrgan (in Dict.): (1) with gen. :-- Heora ǽlc ábyrige ðæs háligwæteres. Ll. Th. i. 226, 24. (2) with acc. :-- Hé ábyrgde ðá forbodenan fictreówes blǽda, Sal. K. 182, 34. v. on-birgan.
Linked entries (variants, parts of a paradigm or derived forms):
Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "á-birgan." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 2.