This paper describes Cross reference services in Knowledge contents based on UCI. Cross references are effective features that can increase the value of the contents. Knowledge contents include academic papers, research reports, archives, historical and cultural heritage, and professional databases. Cross references are consists of reference-to and cited-by links which can be made by reference list in article. Some of cross reference services provided are considered. We designed cross reference services for knowledge contents in Korea and prototype services are provided. The reference linking service in the area of national R&D will enable the linking of heterogeneous information produced at different sources.