Qingdao University Library enjoys the right of interlibrary loan. In order to maximize the convenience and meet the needs of readers, Qingdao University carries out interlibrary loan service through CALIS (China Higher Education Document Guarantee System) and CASHL (China Academic Humanities and Social Sciences Library), which mainly provides paper resources that are not collected by our library, as well as paper books collected by other university libraries. This service is a returned document service.