From: Rabbi Moshe Sofer
To: Rabbi Meir
The Chasam Sofer resolves multiple difficulties raised by his student regarding the laws of writing and signing a get. He argues that the braisa's requirement to hear the husband's voice teaches the need for a physical act rather than excluding a cheresh, and that for the Rambam no agency is required for writing the get. Ultimately he demonstrates that the Rambam follows the Rif's position in line with R' Yitzchak Baal HaTosfos on mipi ksavam, resolving all the difficulties.
Source: Shu"t Chasam Sofer EH II §45