Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "un-ástyrigendlic." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 732.
;adj. Motionless :-- Ic fór of dúne on ða eorðan, and forneáh eallunga unástyrigendlíc bútan gáste læg, Homl. Skt. ii. 23 b, 576. Beón hig unástyriendlíce (immobiles) swylce stán, Cant. M. 16. (Ex. 15, 16).