Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "land-bóc." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 605.
;f. A charter in which land is granted :-- Ðis is ðara xxv hída landbóc ðe Eádgár cyng gebócede Gode and Sca. Marian intó Abbandúne, Cod. Dip. Kmbl. iii. 29, 10. Ic wylle ðæt man ágyfe ðám híwum æt Domrahamme hyra landbéc, ii. 116, 35. Landbéc donatio, Wrt. Voc. ii. 141, 77.