Reference for Niddah 75:27

לאפוקי ממ"ד אי אפשר לפתיחת הקבר בלא דם קמ"ל

the seven days of menstruation, two days after menstruation,<span class="x" onmousemove="('comment',' These two days which begin a new zibah period are not sufficient to establish a major zibah (cf. prev. n. mut. mut). ');">²⁴</span>

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