This document discusses CrossRef in Korea and the services provided by KAMJE (Korean Association of Medical Journal Editors). KAMJE manages several databases covering over 200 Korean medical journals, including KoreaMed, Synapse, KoMCI, and others. Synapse serves as KAMJE's CrossRef platform, providing full text articles and reference linking for over 120 journals. Statistics show significant growth in the number of journals and articles participating in Synapse and CrossRef over the past several years. The benefits of participation include increased international visibility and discoverability of Korean medical research. Challenges include resolving DOI errors and persuading more journals to adopt DOIs, especially for back issues.