Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "þeóf." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 1051.
.Add :-- Man sette heora heáfda swilce óþra ðeófa búton ðám portweallon on ðám heáfodstoccum, Hml. S. 23, 76. Hé genam on his cwearterne twégen ðeófas, and sealde him ðone unlybban, Hml. Th. i. 72, 19. v. firen-, handfangen-, útfangene-þeóf.