From: Rabbi Mordechai Leib Winkler
To: Rabbi Yoshia Buxbaum
The responsum discusses the ruling of the Shulchan Aruch Yoreh Deah 186:3 regarding a woman who does not see blood within 14 days, and then without a fixed time, and the Chavat Da'at's disagreement.
Source: Yoreh Deah I §109