A woman manages her own determination of niddah status: Ketuvot 72a
Checking
A rabbinic enactment to check for blood in the morning and evening daily: Niddah 4b
Checking for blood after dealing with Terumah: Niddah 6a, 11a
The Counting After Seeing Blood
Waiting seven days after seeing the smallest drop of blood: Megillah 28b
Counting the remainder of the 1st day when a menstruating woman sees blood, as the entire 1st day of her 7-day period of waiting: Rosh HaShanah 10a; Niddah 6a