Gittin 8:6-8:9
Gitin8: 6
כָּל הָעֲרָיוֹת שֶׁאָמְרוּ צָרוֹתֵיהֶן מֻתָּרוֹת, הָלְכוּ הַצָּרוֹת הָאֵלּוּ וְנִשָּׂאוּ, וְנִמְצְאוּ אֵלּוּ אַיְלוֹנִיּוֹת — תֵּצֵא מִזֶּה וּמִזֶּה, וְכָל הַדְּרָכִים הָאֵלּוּ בָּהּ.
[Concerning] all the arayos [about] which they said that their co-wives are permitted —- if these co-wives went and were married, and these were found to be ailoniyos, she must leave both of them, and all of these procedures apply to her.
Gitin8: 7
הַכּוֹנֵס אֶת יְבִמְתּוֹ, וְהָלְכָה צָרָתָהּ וְנִשֵֹּׂאת לְאַחֵר, וְנִמְצֵאת זֹאת שֶׁהִיא אַיְלוֹנִית — תֵּצֵא מִזֶּה וּמִזֶּה, וְכָל הַדְּרָכִים הָאֵלּוּ בָּהּ.
[If] one married his yevamah, and her co-wife went and was married to another, and it was discovered that this one is an ailonis, she must leave both of them, and all of these procedures apply to her.
Gitin8: 8
כָּתַב סוֹפֵר גֵּט לָאִישׁ וְשׁוֹבָר לָאִשָּׁה, וְטָעָה וְנָתַן גֵּט לָאִשָּׁה וְשׁוֹבָר לָאִישׁ, וְנָתְנוּ זֶה לָזֶה, וּלְאַחַר זְמַן הֲרֵי הַגֵּט יוֹצֵא מִיַּד הָאִישׁ וְשׁוֹבָר מִיַּד הָאִשָּׁה — תֵּצֵא מִזֶּה וּמִזֶּה, וְכָל הַדְּרָכִים הָאֵלּוּ בָּהּ. רַבִּי אֱלִיעֶזֶר אוֹמֵר: אִם לְאַלְתַּר יָצָא — אֵין זֶה גֵּט; אִם לְאַחַר זְמַן יָצָא — הֲרֵי זֶה גֵּט, לֹא כָל הֵימֶנּוּ מִן הָרִאשׁוֹן לְאַבֵּד זְכוּתוֹ שֶׁל שֵׁנִי.  כָּתַב לְגָרֵשׁ אֶת אִשְׁתּוֹ, וְנִמְלַךְ — בֵּית שַׁמַּאי אוֹמְרִים: פְּסָלָהּ מִן הַכְּהֻנָּה; וּבֵית הִלֵּל אוֹמְרִים: אַף עַל פִּי שֶׁנְּתָנוֹ לָהּ עַל תְּנַאי, וְלֹא נַעֲשָׂה הַתְּנַאי — לֹא פְסָלָהּ מִן הַכְּהֻנָּה.
[If] a scribe wrote a get for a man and a receipt for a woman, and he erred and gave the get to the woman and the receipt to the man, and they gave [them] one to another, and afterward, the get was found in the hand of the man and the receipt in the hand of the woman, she must leave both of them, and all of these procedures apply to her. R' Eliezer says: If it went out immediately, it is not a get; if it went out afterward, it is a get, [because] the first is not believed to abrogate the rights of the second.  [If a man] wrote [a get] to divorce his wife and [then] changed his mind —- Beis Shammai say: He disqualified her from marrying a Kohen; Beis Hillel, however, say: Even if he gave it to her on a condition, and the condition was not met, he did not disqualify her from marrying a Kohen.
Gitin8: 9
הַמְגָרֵשׁ אֶת אִשְׁתּוֹ וְלָנָה עִמּוֹ בַּפֻּנְדְּקִי — בֵּית שַׁמַּאי אוֹמְרִים: אֵינָהּ צְרִיכָה הֵימֶנּוּ גֵּט שֵׁנִי; וּבֵית הִלֵּל אוֹמְרִים: צְרִיכָה הֵימֶנּוּ גֵּט שֵׁנִי. אֵימָתַי? בִּזְמַן שֶׁנִּתְגָּרְשָׁה מִן הַנִּשּׂוּאִין. וּמוֹדִים בְּנִתְגָּרְשָׁה מִן הָאֵרוּסִין שֶׁאֵינָהּ צְרִיכָה הֵימֶנּוּ גֵּט שֵׁנִי, מִפְּנֵי שֶׁאֵין לִבּוֹ גַס בָּהּ.  כְּנָסָהּ בְּגֵט קֵרֵחַ — תֵּצֵא מִזֶּה וּמִזֶּה, וְכָל הַדְּרָכִים הָאֵלּוּ בָּהּ.
One who divorced his wife, and [then] she lodged with him in an inn —- Beis Shammai say: She does not need a second get from him; Beis Hillel, however, say: She needs a second get from him. When? When she was divorced from nisuin. They agree that [if] she was divorced from erusin, she does not need a second get from him because his heart is not close to her.  [If a man] married a woman [on the basis of] a `bald' get, she must leave both of them, and all of these procedures apply to her.