Talmud for Ketubot 11:1
אַלְמָנָה נִזּוֹנֶת מִנִּכְסֵי יְתוֹמִים, מַעֲשֵׂה יָדֶיהָ שֶׁלָּהֶן, וְאֵין חַיָּבִין בִּקְבוּרָתָהּ. יוֹרְשֶׁיהָ, יוֹרְשֵׁי כְתֻבָּתָהּ, חַיָּבִין בִּקְבוּרָתָהּ:
A widow is fed from the property of the orphans [from both land and chattel, this being a condition of the kethubah, viz.: "And you shall sit in my house and be fed from my property"]; her handiwork belongs to them, and they are not obliged to bury her. Her heirs, the inheritors of her kethubah, are obliged to bury her. [For her husband is obliged to bury her in lieu of her inheritance, and now that her heirs (i.e., her children, who are not his) collect her kethubah from the husband's heirs, they bury her. And we incidentally infer that if she died and had not sworn (that she had not collected) her kethubah, in which instance her heirs do not collect her kethubah, the husband's heirs are obliged to bury her.]