Bailly
v. εἰς.
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LSJ
Ion., old Att., Dor. form of εἰς ; all compounds must be sought under εἰς, except a few words which appear only in the form ἐς. Arc., = ἐκ, IG 5(2).6.49 (Tegea, iv BC), al. ; also Delph., BCH 23.611, and Arg., IG 4.492 (Mycenae, vi BC) ; v. ἐκ init.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)