Reference for Niddah 126:15

לאתויי אכלה שום וראתה ואכלה בצלים וראתה כססה פלפלים וראתה

If a woman was in the habit of observing a discharge on the fifteenth day of the month and this was changed to the twentieth day, intercourse is forbidden to her on both days.<span class="x" onmousemove="('comment',' Lit., 'this and this is forbidden', both the fifteenth (in case her first settled period is re-established) and the twentieth (since this date might form now or become her settled period). ');">¹³</span>

Jastrow

Jastrow

Jastrow