Shemot #2: Who were Shifra and Puah?

Last year, I discussed of the midrash that Shifra and Puah = Yocheved and Miriam.

It is interesting that although this is the more famous tradition, it is actually a matter of dispute. Rav says it is Yocheved and Elisheva bat Aminadav, who is the sister of Nachshon ben Aminadav and who married Aharon. (See in parshat Vaera, in Shemot 6:23.) It is R' Shmuel bar Nachman who says Yocheved and Miriam. The latter is the more mainstream midrash, in the sense that many other midrashim refer to Miriam as the other midwife.