Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "ganra." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 361.
.Add :-- Anser [vel ganra (added in another hand)] hwít gós, Wülck. Gl. 284, 13. Gandra (ganra, v. l.) anser, Ælfc. Gr. Z. 43, 14. Gif wíf eteð hanan flǽsc oððe ganran, Lch. iii. 144, 24. ¶ in a place-name :-- Andlang weges upp on gandran dúne, C. D. v. 166, 6.