She’erith Yoseph [responsa].

The brother-in-law of the Rem’a, R. Joseph ben Mordechai Gershon served on the Cracow Beth Din. His responsa overwhelmingly deal with his particular focus, financial and commercial matters. He corresponded with leading rabbis of his day, including the MaHaRSHa”L (responsum 17) and R. Meir Katzenellenbogen (responsum 1). Rabbi Dr. Irving Agus (1910-84) was a Jewish historian who pioneered the usage of responsa as a historical source. After serving as the dean of Jerusalem’s Harry Fischel Institute, he accepted a teaching position at Yeshiva University, where he spent most of his career. In later years, he edited the Jewish Quarterly Review.