From: Rabbi Moshe Sofer
To: Rabbi Hertz Scheyer
A wide-ranging scholarly exchange with Rabbi Hertz Scheyer of Mainz addressing the Ra'avan's interpretation of muktzeh rules for menorahs on Shabbos, the Rokeach's position on netilas yadayim for small amounts of bread, and the Rambam's ruling permitting benefit from gid hanasheh.
Source: Shu"t Chasam Sofer OC §86