Reference for Eduyot 4:7
הָאִשָּׁה מִתְקַדֶּשֶׁת בְּדִינָר וּבְשָׁוֶה דִינָר, כְּדִבְרֵי בֵית שַׁמָּאי. וּבֵית הִלֵּל אוֹמְרִים, בִּפְרוּטָה וּבְשָׁוֶה פְרוּטָה. וְכַמָּה הִיא פְרוּטָה, אֶחָד מִשְּׁמֹנָה בְאִסָּר הָאִיטַלְקִי. בֵּית שַׁמַּאי אוֹמְרִים, פּוֹטֵר הוּא אֶת אִשְׁתּוֹ בְגֵט יָשָׁן, וּבֵית הִלֵּל אוֹסְרִין. אֵיזֶהוּ גֵט יָשָׁן. כָּל שֶׁנִּתְיַחֵד עִמָּהּ אַחַר שֶׁכְּתָבוֹ לָהּ. הַמְגָרֵשׁ אֶת אִשְׁתּוֹ וְלָנָה עִמּוֹ בְפֻנְדְּקִי, בֵּית שַׁמַּאי אוֹמְרִים, אֵינָהּ צְרִיכָה מִמֶּנּוּ גֵט שֵׁנִי. וּבֵית הִלֵּל אוֹמְרִים, צְרִיכָה מִמֶּנּוּ גֵט שֵׁנִי. אֵימָתַי, בִּזְמַן שֶׁנִּתְגָּרְשָׁה מִן הַנִּשּׂוּאִין. אֲבָל אִם נִתְגָּרְשָׁה מִן הָאֵרוּסִין, אֵינָהּ צְרִיכָה מִמֶּנּוּ גֵט שֵׁנִי, מִפְּנֵי שֶׁאֵין לִבּוֹ גַס בָּהּ:
A woman is betrothed with a dinar [ninety-six barley-corns weight of silver] or with the worth of a dinar, according to the words of Beth Shammai. And Beth Hillel say: with a p'rutah [a half barley-corn weight of silver] or with the worth of a p'rutah. And how much is a p'rutah? One-eighth of an Italian issar [four barley-corns weight of silver, so called because it was issued in Italy.] Beth Shammai say: A man may divorce his wife with an old get [which he wrote to divorce his wife, continuing to live with her after he wrote the get. Beth Shammai hold that we do not decree against it lest people say: "Her get preceded her son," i.e., lest a year or two pass between the writing and the giving and she have children from him in the interim and then be divorced with that get — so that people, seeing the get as antedating the birth of her son, might come to think that the get were given her at the time of writing and come to cast a blemish upon the child, saying that it was born of an unmarried woman.] And Beth Hillel forbid it. Which is "an old get"? A get, after the writing of which he continued living with her. [The halachah: One may not divorce his wife with an old get. And if he divorced her and went to a different country, she may remarry by it ab initio.] If one divorced his wife, and she spent the night with him at an inn, [there being witnesses to their having been alone together, but not to their having cohabited], Beth Shammai say: She does not require a second get from him. Beth Hillel say: she requires a second get from him. [Beth Hillel hold that witnesses to their being alone together are (considered) witnesses to cohabitation. And since a man does not cohabit promiscuously when he can do so legitimately, (we assume that) he betrothed her with this cohabitation. And Beth Shammai hold that we do not consider witnesses to their being alone witnesses to cohabitation until they actually observe her in the act.] When is this so? If she were divorced from marriage. But if she were divorced from betrothal, she does not require a second get from him, for he is not that familiar with her (and is assumed not to have cohabited with her.)