Jerusalem Talmud Yevamot 2:7

משנה: מִי שֶׁקִּידֵּשׁ אַחַת מִשִִּֽׁתֵּי אֲחָיוֹת וְאֵינוֹ יוֹדֵעַ אֵיזֶה מֵהֶן קִידֵּשׁ נוֹתֵן גֵט לָזוֹ וְגֵט לָזוֹ. מֵת ולוֹ אָח אֶחָד חוֹלֵץ לִשְׁתֵּיהֶן. הָיוּ לוֹ שְׁנַיִם אֶחָד חוֹלֵץ וְאֶחָד מְייַבֵּם. קָֽדְמוּ וְכָֽנְסוּ אֵין מוֹצִיאִין מִיָּדָם. MISHNAH: If somebody gave qiddushin to one of two sisters but he does not know to which one of them, he gives a bill of divorce to each¹⁴⁸Both are forbidden to him since each one is possibly hi his sister-in-law’s sister.. If he died and has one brother, that one has to perform ḥalîṣah with both sisters. If he had two [brothers], one performs ḥalîṣah and one may marry in levirate¹⁵⁰If the one who performed ḥalîṣah had received qiddushin from the deceased, the other one is free to marry his brother. If she did not get qiddushin, then the levirate is valid.. If both married without asking, one¹⁵¹The court does not intervene since one has correctly married in levirate and the other is free to marry his brother since she had no qiddushin. does not remove [the women] from them.

הלכה: מִי שֶׁקִּידֵּשׁ אַחַת מִשְּׁתֵּי אֲחָיוֹת וְאֵינוֹ יוֹדֵעַ אֵיזֶה מֵהֶן קִידֵּשׁ נוֹתֵן גֵט לָזוֹ וְגֵט לָזוֹ. מֵת ולוֹ אָח אֶחָד חוֹלֵץ לִשְׁתֵּיהֶן. בְּכָל־אָתָר אַתְּ אָמַר. אֵין חֲלִיצָה אַחַר חֲלִיצָה. וְהָכָא אַתְּ אָמַר הָכֵין. כָּאן בְּװַדַּאי כָּאן בְּסָפֵק. הָיוּ לוֹ שְׁנַיִם אֶחָד חוֹלֵץ וְאֶחָד מְייַבֵּם. בְּכָל־אָתָר אַתְּ אָמַר. בְּכָל־מָקוֹם שֶׁאוֹמְרִים לוֹ. ייַבֵּם. אֵין אוֹמְרִים לוֹ. חֲלוֹץ. וְהָכָא אָמַר אָכֵין. כָּאן בְּוַדַּאי כָּאן בְּסָפֵק. קָֽדְמוּ וְכָֽנְסוּ אֵין מוֹצִיאִין מִיָּדָן. HALAKHAH: “If somebody gave qiddushin to one of two sisters but he does not know to which one of them, he gives a bill of divorce to each. If he died and has one brother, that one has to perform ḥalîṣah with both sisters.” Everywhere else you say¹⁵²Mishnah 5:1. “there cannot be ḥalîṣah after ḥalîṣah” but here you say so? There if it is certain, here one is in doubt¹⁵³It is impossible to do otherwise.. “If he had two [brothers], one performs ḥalîṣah and one may marry in levirate.” Everywhere else you say, in any case one asks him to perform the levirate one does not say perform ḥalîṣah; but here you say so? There if it is certain, here one is in doubt. “If both married without asking, one does not remove [the women] from them.”