Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "hálsere." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 505.
.Add: a soothsayer (?), diviner, an augur :-- Hálsere commentarius (cf. cotmmenta, i. ficta, fraudes, 39), Wrt. Voc. ii. 132, 42. Hálseras extipices, i. auruspices, 145, 18. v. hǽlsere.