Reference for Bava Batra 123:3

אמרו ליה רב כהנא ורב אסי לרב ויקנה כנגד ראש תור שתיק רב

If the seller draws one of two parallel boundaries shorter than the other, Rab says that the purchaser obtains only the width of the shorter line.<span class="x" onmousemove="('comment',' Rab assumes that the field sold is to be a parallelogram, v. fig. I. ');">²</span>

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