Talmud for Gittin 6:2
הָאִשָּׁה שֶׁאָמְרָה, הִתְקַבֵּל לִי גִטִּי, צְרִיכָה שְׁתֵּי כִתֵּי עֵדִים, שְׁנַיִם שֶׁאוֹמְרִים בְּפָנֵינוּ אָמְרָה וּשְׁנַיִם שֶׁאוֹמְרִים בְּפָנֵינוּ קִבֵּל וְקָרַע, אֲפִלּוּ הֵן הָרִאשׁוֹנִים וְהֵן הָאַחֲרוֹנִים, אוֹ אֶחָד מִן הָרִאשׁוֹנִים וְאֶחָד מִן הָאַחֲרוֹנִים וְאֶחָד מִצְטָרֵף עִמָּהֶן. נַעֲרָה הַמְאֹרָסָה, הִיא וְאָבִיהָ מְקַבְּלִין אֶת גִּטָּהּ. אָמַר רַבִּי יְהוּדָה, אֵין שְׁתֵּי יָדַיִם זוֹכוֹת כְּאַחַת, אֶלָּא אָבִיהָ מְקַבֵּל אֶת גִּטָּהּ בִּלְבָד. וְכֹל שֶׁאֵינָהּ יְכוֹלָה לִשְׁמֹר אֶת גִּטָּהּ, אֵינָהּ יְכוֹלָה לְהִתְגָּרֵשׁ:
If a woman said: "Receive my get for me," she needs [to bring before us] two sets of witnesses: two who say: "Before us she told" [him to receive it], and two who say: "Before us he received it and he tore it." [This, in a time of shmad (enforced conversion), when (observance of) mitzvoth was decreed against, and they would tear the get immediately, so that it not be seen.] — even if they [those before whom she told him to receive it] were (both) the first and the last [those who saw him receive it], or one from the first set and one from the second and another joining them [i.e., complementing each one]. A betrothed maiden, she or her father receives her get. [She has a "hand," for she is of age, and her father, too, is authorized to receive it.] R. Yehudah said: Two "hands" cannot be invested as one. Rather, her father alone receives her get. And any woman who cannot guard her get cannot be divorced, [even if her father receives it, it being written (Deuteronomy 24:1): "And he shall send her from his house" — one who is sent and does not return; to exclude this one, who is sent and does return.]