Reference for Bava Batra 345:10

ואלא הא דתניא כשם שמוציאין הן שטר חוב על אחרים כך מוציאין זה על זה במאי קמיפלגי

Raba, however, said: Brothers are different because they pilfer from one another.<span class="x" onmousemove="('comment',' In the case of a bequeathed estate. All the brothers being heirs to it, every one considers himself entitled to appropriate as much of it as he possibly can. It is for this reason only that it was ordained that the brother who claims, against the statement of the other brothers, to be the sole owner of an inherited bond, must produce proof. As this unlawful appropriation could not apply to the case of a stranger, proof in that case is not required. ');">²⁸</span> Others say, Raba said: Whence do I derive this?<span class="x" onmousemove="('comment',' That apart from the production of the bond no other proof is required. ');">²⁹</span> — For it was taught: 'The brother who presents the bond of indebtedness must produce proof'.<span class="x" onmousemove="('comment',' V. supra notes, 11, 15. ');">³⁰</span>

Jastrow