Reference for Bava Metzia 50:10

אמר רב זביד לא קשיא הא בכובי וכסי הא בסכיני והמניק בכובי וכסי לא יגע בסכיני והמניק נוטל ומכריז

— Because we say, A person hid them here, and if he [the finder] takes them, their owner has no means of identifying them. Therefore he must leave them until their owner comes and takes them. But why? let the knot be a means of identification!<span class="x" onmousemove="('comment',' The owner can say where they were tied together. ');">⁹</span>

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