Impact of acupuncture treatment on the lumbar surgery rate for low back pain in Korea: A nationwide matched retrospective cohort study. - Koh, Wonil; Kang, Kyungwon; Lee, Yoon Jae; Kim, Me-riong; Shin, Joon-Shik; Lee, Jinho; Lee, Jun-Hwan; Shin, Kyung-Min; Ha, In-Hyuk (PLoS ONE, 2018)