Pesachim, Chapter 4, Mishnah 6. This mishnah discusses the types of work that may be done on the eve of Pesach, even in a place where the custom is not to work already from the morning of the fourteenth.
The view of Rabbi Meir:
"Kol melachah shehischil bah kodem le'arba'ah asar - gomrah be'arba'ah asar" - work that a person began on the day before the fourteenth may be completed on the fourteenth, even in a place where the custom is not to work in the morning. However, according to the Gemara this permission applies only to work that is needed for the festival, for the sake of Yom Tov; work that is not needed for Yom Tov is not included in this ruling.
"Aval lo yaschil bah bitchilah be'arba'ah asar, af al pi sheyachol legomrah" - one may not begin a new piece of work on the fourteenth, even if it could be completed before midday and finished already during the morning hours. Only work that is a continuation of work already begun is permitted.
The view of the Sages - three trades:
"VaChachamim omrim: shalosh umaniyos osin melachah be'erev Pesach ad chatzos" - three types of craftsmen may do their work on the eve of Pesach until midday, even in a place where work is not done before midday. The Rosh explains that these craftsmen may engage in their work even if they began it on the fourteenth itself - unlike Rabbi Meir, who holds that one does not begin work on the fourteenth - provided that they can finish by midday.
The reason: these three trades are considered to serve the needs of the festival to a greater degree, since there are situations in which they are permitted even on Chol HaMoed itself, albeit under certain circumstances. And since there is a leniency regarding them on Pesach and on Chol HaMoed, we are more lenient with them on the eve of Pesach.
"Ve'elu hen: hachayatin vehasaparim vehakovsin":
Hachayatin - the tailors. On Chol HaMoed it is permitted to sew certain things when the work is not done in a professional manner, and therefore on the fourteenth this was permitted even when done by a professional, since on the fourteenth we are more lenient.
Hasaparim vehakovsin - the barbers and the launderers. In Maseches Moed Katan we learned that one who arrives from overseas or who is released from prison may cut his hair and launder his clothes on Chol HaMoed. Therefore it was permitted to cut hair and launder on the fourteenth before midday, even in a place where work is generally not done until midday.
The addition of Rabbi Yosi beRabbi Yehudah:
"Rabbi Yosi beRabbi Yehudah omer: af haratzanin" - the shoemakers, who work with the leather of shoes. His reasoning: since on Chol HaMoed they were permitted to repair the shoes of the pilgrims who came up to Jerusalem for Yom Tov, on the eve of Pesach, when we are more lenient, they were permitted even to make new shoes.
The reasoning of the Sages who disagree with him: one cannot derive permission to begin a piece of work from permission to complete a piece of work. The repairing of shoes that was permitted on Chol HaMoed is only the end of the process, and one cannot derive from it permission for the very beginning of making new shoes. Rabbi Yosi beRabbi Yehudah, however, holds that one can indeed learn one from the other, and therefore he permitted the shoemakers as well to do their work on the eve of Pesach.
In summary: in this mishnah the Tannaim disagree about which types of work are permitted on the eve of Pesach in a place where the custom is not to work. According to Rabbi Meir, work that was begun before the fourteenth may be completed on the fourteenth, provided it is needed for the festival, but one may not begin it from scratch. According to the Sages, three trades - tailors, barbers and launderers - may do their work until midday and may even begin it on the fourteenth, because these types of work are permitted to a certain extent even on Chol HaMoed. And Rabbi Yosi beRabbi Yehudah added the shoemakers as well, while the Sages disagreed with him over whether one may derive permission to begin a piece of work from permission to complete one.