Reference for Yevamot 4:3
שׁוֹמֶרֶת יָבָם שֶׁנָּפְלוּ לָהּ נְכָסִים, מוֹדִים בֵּית שַׁמַּאי וּבֵית הִלֵּל שֶׁמּוֹכֶרֶת, וְנוֹתֶנֶת, וְקַיָּם. מֵתָה, מַה יַּעֲשׂוּ בִכְתֻבָּתָהּ וּבַנְּכָסִים הַנִּכְנָסִים וְיוֹצְאִין עִמָּהּ, בֵּית שַׁמַּאי אוֹמְרִים, יַחֲלֹקוּ יוֹרְשֵׁי הַבַּעַל עִם יוֹרְשֵׁי הָאָב. וּבֵית הִלֵּל אוֹמְרִים, נְכָסִים בְּחֶזְקָתָן, כְּתֻבָּה בְּחֶזְקַת יוֹרְשֵׁי הַבַּעַל, נְכָסִים הַנִּכְנָסִים וְיוֹצְאִים עִמָּהּ בְּחֶזְקַת יוֹרְשֵׁי הָאָב:
A shomereth yavam [a woman awaiting yibum] to whom property fell [from her father's house] — Beth Shammai and Beth Hillel concur that she may sell it or give it away, and that it (whatever she does) stands. If she died, what should they do with her kethubah [the hundred or two hundred, and the addition, and the dowry that she brought to him and for which he assumed responsibility] and the property which goes in and out with her [nichsei melog (usufruct), which when she goes in to her husband goes in with her, and which, when she goes out, goes out with her]? Beth Shammai say: The heirs of the husband and the heirs of the father should divide it [for there is a possibility that she is (considered) married (to the yavam), so that the yavam acquires half of her property, a husband inheriting his wife, her being possibly married to him endowing him with half.], and Beth Hillel say: The property [tzon barzel (mortmain)] remains in its status. [And Beth Hillel did not specify whether it reverts to the heirs of the woman, the property having been hers, or to the heirs of the husband, who had assumed responsibility for it. As to the halachah, they divide it even according to Beth Hillel.] Her kethubah is in the status (i.e., the ownership) of the heirs of the husband. The property which goes in and out with her is in the status of the heirs of the father.