Reference for Bava Batra 169:6
קתני מיהא ברשות הרבים ובחצר שאינה של שניהן
it or has removed it from the seller's premises.<span class="x" onmousemove="('comment',' Into his own, into an alley. or the like. ');"><sup>20</sup></span> [If the purchase was] on the premises of the buyer, he acquires possession as soon as the seller has consented [to the terms of the sale].<span class="x" onmousemove="('comment',' Though no measuring of the commodity has yet taken place. ');"><sup>21</sup></span> [If the purchase was] on the premises of one with whom it had been deposited [by the seller]. possession cannot be acquired [by the buyer] until [the owner of the premises] has consented<span class="x" onmousemove="('comment',' At the request of the seller. ');"><sup>22</sup></span> [to allow to the buyer a portion of his premises on which to effect acquisition of ownership], or until [the buyer] had hired the place it occupies. At any rate, it is taught here [that possession by means of one's vessel may be acquired] in reshuth harabbim and in a courtyard which belongs to neither of them.