Reference for Rosh Hashanah 27:1

וצריכא דאי אשמעינן הלכה כר"ש שזורי ה"א משום דקסבר יש בילה קמ"ל לכל אין בילה

And all three dicta of Samuel are necessary.<span class="x" onmousemove="('comment',' For making clear to us his point of view.');">¹</span> For if he had told us only that the law follows R'Simeon B'Shezuri, I should have said that his reason was because we can rely on mixing; he tells us therefore that mixing is not to be relied on for anything.

Jastrow