Two-Layer Retrieval-Augmented Generation Framework for Low-Resource Medical Question Answering Using Reddit Data: Proof-of-Concept Study - Sudeshna Das; Yao Ge; Yuting Guo; Swati Rajwal; JaMor Hairston; Jeanne Powell; Drew Walker; Snigdha Peddireddy; Sahithi Lakamana; Selen Bozkurt; Matthew Reyna; Reza Sameni; et al. (Journal of Medical Internet Research)