Reference for Bava Kamma 79:7
א"ר חסדא ר' ישמעאל בנו של ר' יוחנן בן ברוקה היא דתניא (שמות כא, ל) ונתן פדיון נפשו דמי ניזק ר' ישמעאל בנו של רבי יוחנן בן ברוקה אומר דמי מזיק
as it has been taught: R. Eliezer b. Jacob says: Whether in the case of <i>Tam</i> or in the case of <i>Mu'ad</i>, if precautions of [at least] some inferior sort have been taken to control the ox, there would be no liability. The new point made known to us by R. Jacob would thus have been that guardians should be appointed even in the case of <i>Tam</i> to collect payment out of its body. [Why then did Raba explain the former statement of R. Jacob to refer only to <i>Mu'ad</i>? Why did he not explain it to refer to <i>Tam</i> also?] — [In answer] he<span class="x" onmousemove="('comment',' I.e., Rabina. ');"><sup>6</sup></span>