Date: 13 Shevat 5579
From: Rabbi Moshe Sofer
To: Rabbi Ephraim Zalman Margaliot
The responsum addresses the book 'Noga Tzedek' and its author, R. Aaron Chorin, who promotes Reform practices, and the author's efforts to counter these challenges to traditional Judaism.
Source: Shu"t Chasam Sofer Collected §90