Talmud for Ketubot 9:5
כָּתַב לָהּ, נֶדֶר וּשְׁבוּעָה אֵין לִי עָלָיִךְ, אֵין יָכוֹל לְהַשְׁבִּיעָהּ, אֲבָל מַשְׁבִּיעַ הוּא אֶת יוֹרְשֶׁיהָ וְאֶת הַבָּאִים בִּרְשׁוּתָהּ. נֶדֶר וּשְׁבוּעָה אֵין לִי עָלַיִךְ וְעַל יוֹרְשַׁיִךְ וְעַל הַבָּאִים בִּרְשׁוּתִיךְ, אֵינוֹ יָכוֹל לְהַשְׁבִּיעָהּ, לֹא הִיא וְלֹא יוֹרְשֶׁיהָ וְלֹא אֶת הַבָּאִים בִּרְשׁוּתָהּ. אֲבָל יוֹרְשָׁיו מַשְׁבִּיעִין אוֹתָהּ, וְאֶת יוֹרְשֶׁיהָ וְאֶת הַבָּאִים בִּרְשׁוּתָהּ. נֶדֶר וּשְׁבוּעָה אֵין לִי וְלֹא לְיוֹרְשַׁי וְלֹא לַבָּאִים בִּרְשׁוּתִי עָלַיִךְ וְעַל יוֹרְשַׁיִךְ וְעַל הַבָּאִים בִּרְשׁוּתִיךְ, אֵינוֹ יָכוֹל לְהַשְׁבִּיעָהּ, לֹא הוּא וְלֹא יוֹרְשָׁיו וְלֹא הַבָּאִים בִּרְשׁוּתוֹ, לֹא אוֹתָהּ וְלֹא יוֹרְשֶׁיהָ וְלֹא הַבָּאִין בִּרְשׁוּתָהּ:
If he wrote to her: "I will impose upon you neither vow nor oath," he cannot make her swear; but he can make her heirs swear [If he divorced her, and she died, and her heirs claim her kethubah from him, they swear the "oath of the heirs," viz.: She did not tell us at her death, and she did not tell us before that, and we did not find among her deeds, that her kethubah had been paid.]; and (he can make) those coming by her authority (swear). [If she had sold her kethubah to others, and she had been divorced and had died, and the buyers had come to claim her kethubah, they, too, swear the oath of the heirs.] (If he wrote:) "I will impose neither vow nor oath upon you, your heirs, or those who come by your authority," he cannot cause to swear either her or her heirs or those who come by her authority; but his heirs can cause to swear: her, her heirs, and those who come by her authority. [If she were widowed and she or her heirs claimed it from the orphans, they require an oath, for he exempted them only from (the exaction of an oath by) him, if her kethubah were claimed in his lifetime.] (If he wrote:) "Neither I, nor my heirs, nor those who come by my authority [(if I sell my property, and you come to collect from the buyers)] will impose either vow or oath upon you, your heirs, or those who come by your authority," neither he nor his heirs, nor those who come by his authority can cause to swear either her, her heirs, or those who come by her authority.