| Affiliation: | 1. Department of Pediatrics, College of Medicine, St. Vincent's Hospital, The Catholic University of Korea, Gyeonggi, Korea;2. Department of Pediatrics, College of Medicine, Yeouido St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea;3. Department of Pediatrics, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea;4. Department of Biostatistics, Clinical Research Coordinating Center, The Catholic University of Korea, Seoul, Korea |
