Reference for Gittin 52:4

רב חסדא אמר אבימי משום תקנת עגונות אמרי לה ר"מ ואמרי לה ר"א

Some again say it follows R. Eleazar who held that the witnesses to delivery make [the Get] effective, and therefore by rights even the formula [of the Get] should not be written beforehand,<span class="x" onmousemove="('comment',' For fear that it may lead to the writing of the substantive part. ');">³</span>

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