Reference for Shabbat 53:10
רב פפא אמר אף כל לאתויי כלאים כלאים בהדיא כתיבי ביה (דברים כב, יא) לא תלבש שעטנז צמר ופשתים יחדיו ס"ד אמינא ה"מ דרך לבישה אבל בהעלאה כל תרי מיני אסור
R. Papa said: 'So all [are of wool or flax],<span class="x" onmousemove="('comment',' In the first citation of the Tanna of the School of R. Ishmael, supra 26b. ');"><sup>18</sup></span> is to include kil'ayim.<span class="x" onmousemove="('comment',' V. Glos. I.e., only a mixture of wool or flax is forbidden, but no other. Accordingly it does not relate to defilement at all, and does not contradict the other teaching of the School of R. Ishmael. — Rashi reads at the beginning of this passage, For R. Papa said, since this dictum of R. Papa explains why in his opinion the two are not contradictory. ');"><sup>19</sup></span>