Reference for Ketubot 13:1
שְׁנֵי דַיָּנֵי גְזֵרוֹת הָיוּ בִירוּשָׁלַיִם, אַדְמוֹן וְחָנָן בֶּן אֲבִישָׁלוֹם. חָנָן אוֹמֵר שְׁנֵי דְבָרִים, אַדְמוֹן אוֹמֵר שִׁבְעָה. מִי שֶׁהָלַךְ לִמְדִינַת הַיָּם וְאִשְׁתּוֹ תוֹבַעַת מְזוֹנוֹת, חָנָן אוֹמֵר, תִּשָּׁבַע בַּסּוֹף וְלֹא תִשָּׁבַע בַּתְּחִלָּה. נֶחְלְקוּ עָלָיו בְּנֵי כֹהֲנִים גְּדוֹלִים וְאָמְרוּ, תִּשָּׁבַע בַּתְּחִלָּה וּבַסּוֹף. אָמַר רַבִּי דוֹסָא בֶן הַרְכִּינָס כְּדִבְרֵיהֶם. אָמַר רַבָּן יוֹחָנָן בֶּן זַכַּאי, יָפֶה אָמַר חָנָן, לֹא תִשָּׁבַע אֶלָּא בַסּוֹף:
There were two judges of decrees in Jerusalem, Admon and Chanan ben Avishalom. [They made decrees against robbers and imposed penalties upon them.] Chanan says two things [with which the sages do not concur]; Admon says seven. If one went abroad and his wife claimed food, Chanan says: She swears at the end [When they hear that he died, and she comes to claim her kethubah, she swears that she did not hold back aught belonging to her husband.], and she does not swear at the beginning [when she claims food. Rambam explains: "She swears at the end": When her husband comes and denies what she says, saying that he did leave her food, she swears that he had left her nothing.] The sons of the high-priests differed with him, saying that she swears in the beginning and at the end. R. Dossa b. Harkinas ruled in accordance with them. R. Yochanan b. Zakkai said: Chanan said well. She swears only at the end [and the halachah is in accordance with him. And it is only after three months from the husband's going abroad that food is provided for his wife if she claims food; but not before this time. For it is assumed that a man does not go abroad, leaving his house "empty."]