Bava Basra9: 5
הַשּׁוֹלֵחַ סִבְלוֹנוֹת לְבֵית חָמִיו, שָׁלַח שָׁם מֵאָה מָנֶה, וְאָכַל שָׁם סְעוּדַת חָתָן אֲפִלּוּ בְדִינָר — אֵינָן נִגְבִּין. לֹא אָכַל שָׁם סְעוּדַת חָתָן — הֲרֵי אֵלּוּ נִגְבִּין. שָׁלַח סִבְלוֹנוֹת מְרֻבִּין שֶׁיַּחְזְרוּ עִמָּהּ לְבֵית בַּעְלָהּ — הֲרֵי אֵלּוּ נִגְבִּין. סִבְלוֹנוֹת מֻעָטִין שֶׁתִּשְׁתַּמֵּשׁ בָּהֶן בְּבֵית אָבִיהָ — אֵינָן נִגְבִּין.
[If] one sent wedding gifts to the house of his father-in-law, [even if] he sent a hundred maneh there, and he ate there a groom's meal worth [as little] as a dinar, they cannot be reclaimed. [If] he did not eat a groom's meal there, they can be re-claimed. [If] he sent many wedding gifts, [on the understanding] that they return with her to her husband's house, they can be reclaimed. [If he sent] few wedding gifts [on the understanding] that she use them in her father's house, they cannot be re-claimed.
Bava Basra9: 6
שְׁכִיב מְרַע שֶׁכָּתַב כָּל נְכָסָיו לַאֲחֵרִים, וְשִׁיֵּר קַרְקַע כָּל שֶׁהוּא — מַתְּנָתוֹ קַיֶּמֶת. לֹא שִׁיֵּר קַרְקַע כָּל שֶׁהוּא — אֵין מַתְּנָתוֹ קַיֶּמֶת.  לֹא כָתַב בָּהּ שְׁכִיב מְרַע, הוּא אוֹמֵר שְׁכִיב מְרַע הָיָה, וְהֵן אוֹמְרִים בָּרִיא הָיָה — צָרִיךְ לְהָבִיא רְאָיָה שֶׁהָיָה שְׁכִיב מְרַע; דִּבְרֵי רַבִּי מֵאִיר. וַחֲכָמִים אוֹמְרִים: הַמּוֹצִיא מֵחֲבֵרוֹ עָלָיו הָרְאָיָה
[If] one who was lying ill wrote [away] all his property to others, but retained some property, his gift is upheld. [If] he did not retain any property, his gift is not upheld.  [If] he did not record in it [that he was] lying ill, [and] he says that he was ly-ing ill, whereas they say that he was healthy, he must bring proof that he was lying ill; [these are] the words of R' Meir. But the Sages say: The one who exacts from another must bring the proof.