Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "mǽne." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 628.
;adj.I.mean, wicked, false, evil :-- Synna lustas mǽne módlufan the pleasures of sin, vicious love, Exon. 71 a; Th. 364, 26; Jul. 370. Hygeleáse mǽne mad and false (the rebel angels), Cd. 4; Th. 4, 11; Gen. 52. Þurh mǽnra hand searonettum beseted. Andr. Kmbl. 1882 ; An. 943. II. the word however occurs most often in reference to oaths :-- Se ðe his þances mǽnne áþ swerige and hé wite ðæt hé mǽne biþ æfter ðam qui sua sponte perjuraverit et postea scit quod perjurus est, L. Ecg. C. 34; Th. ii. 158, 20, 14, 16.