Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "mangere." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 63.
, es; m. A monger (in iron-monger, cheese-monger, &c. ), merchant, trader, dealer :-- Mangere mercator vel negotiator, Wrt. Voc. i. 73, 72. Hwæt sægst ðu, mancgere (mercator) ? Coll. Monast. Th. 26, 23. Ne preóst ne beó mangere a priest shall not be a merchant (cf. Icel. prestar skulu eigi fara með mangi né okri), L. Ælfc. C. 30; Th. ii. 354, I. Wé lǽraþ ðæt preósta gehwilc tilige him rihtlíce and ne beó ǽnig mangere mid unrihte, L. Edg. C. 14; Th. ii. 246, 24.