Reference for Pesachim 4:6
רַבִּי מֵאִיר אוֹמֵר, כָּל מְלָאכָה שֶׁהִתְחִיל בָּהּ קֹדֶם לְאַרְבָּעָה עָשָׂר, גּוֹמְרָהּ בְּאַרְבָּעָה עָשָׂר. אֲבָל לֹא יַתְחִיל בָּהּ בַּתְּחִלָּה בְאַרְבָּעָה עָשָׂר, אַף עַל פִּי שֶׁיָּכוֹל לְגָמְרָהּ. וַחֲכָמִים אוֹמְרִים, שָׁלֹשׁ אֻמָּנֻיּוֹת עוֹשִׂין מְלָאכָה בְעַרְבֵי פְסָחִים עַד חֲצוֹת, וְאֵלּוּ הֵן, הַחַיָּטִים, הַסַּפָּרִים וְהַכּוֹבְסִין. רַבִּי יוֹסֵי בַּר יְהוּדָה אוֹמֵר, אַף הָרַצְעָנִים:
R. Meir says: All work [needed for the festival], which one began before the fourteenth, may be completed on the fourteenth [even in a place where it was the custom not to work. But work not needed for the festival may be done in a place where it was the custom to work. And in a place where it was the custom not to work, even if he began such work before the fourteenth, he may not complete it.] But he may not begin it on the beginning of the fourteenth, even if he can complete it. And the sages say: Three craftsmen may follow their trade on Pesach eve until mid-day: tailors [They are permitted to work on the fourteenth in all places, for we find a leniency in respect to tailoring on chol hamoed (the intermediate days of the festival) that we do not find in respect to other trades — that one who is not expert in it may sew as he regularly does, for which reason on the fourteenth, which is of lesser sanctity than chol hamoed, even a professional (tailor) may work.], barbers, and washermen. [For one who comes from abroad and one who is released from prison may cut his hair and wash his clothing on chol hamoed. And since we find a leniency on chol hamoed, on the fourteenth, which is of lesser sanctity, it is permitted to all.] R. Yossi b. Yehudah says: Even the cobblers. [For the festival pilgrims repair their shoes on the festival. And the sages hold that we do not derive the beginning of the cobblers' work — the making of new shoes — from its end, the repairing of shoes for the festival pilgrims. The halachah is in accordance with the sages.]