Efficacy and safety of Galgeun-tang-ga-cheongung-sinyi for nasal congestion with common cold: A study protocol for randomized, double-blind, placebo-controlled, parallel, multicenter clinical trial - Seong-Cheon Woo; Yee Ran Lyu; Byong-Kab Kang; Bok-Nam Seo; Ae-Ran Kim; Boram Lee; Yang Chun Park (PLoS ONE, 2026)