Tosefta for Megillah 45:5

On Yom Tov five [read from the Torah], on Yom Kippur six, and on Shabbat seven. If they wanted to add, they may not add, the words of Rabbi Yishmael. Rabbi Akiva says, on Yom Tov five, on Yom Kippur six, and on Shabbat seven, and if they wanted to add, they may add. Everyone counts toward the quorum of seven [readers], even a woman, even a minor. [However,] we do not bring up a woman to read in public.