From: Rabbi Akiva Eiger
To: Unknown recipient
Rabbi Akiva Eiger continues his exchange with a colleague, refuting proofs advanced by a third authority (the Sh"Y) that writing is not equivalent to speech. He argues the Megillah sugya demonstrates fulfillment through reading, not writing, that the Terumas HaDeshen's ruling on written oaths is limited to past-tense formulations, and that the analogy to Sefiras HaOmer is speculative. The discussion concludes with tzarich iyun on the Megillah sugya.
Source: Shu"t Rabbi Akiva Eiger §32