Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "Gallias." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 28.
, Gallie, Galleas; gen. Gallia; pl. m. The Gauls, the Franks; Galli, ōrum; Galliæ, ārum; pl. m :-- Ðǽr wæs Gallia ofslagen twá-hund þúsenda ducenta millia Gallōrum interfecta sunt, Ors. 5, 8; Bos. 107, 33; Hav. 329, 8 : 4, 7; Bos. 89, 7. Gefeaht wið Gallie adversum Gallos conflixit, 4, 7; Bos. 89, 8; Hav. 251, 2. Hú sceolan we dón mid Gallia and Brytta bisceopum quālĭter dēbēmus cum Galliārum Brittaniārumque episcŏpis ăgĕre? Bd. 1. 27; S. 492, 10. Biscop Gallia ríces bishop of the kingdom of the Gauls [Galliārum], Bd. 5, 8; S. 621, 39.