OCLC’s WorldCat approaches 475 million bibliographic records. Many of those records have been created manually by members of OCLC’s worldwide cooperative. Others have been added to WorldCat en masse from institutions large and small, from national libraries, from cultural heritage institutions, or from rural public libraries.
The paper describes the upload of bibliographic records from the COBIB.SI shared database as well as holdings data of certain Slovenian libraries into WorldCat, the Online Union Catalogue. In 2009, the initial upload of records was made and a regular quarterly upload followed.
The article presents downloading of bibliographic records from foreign databases to the COBISS system, serials from the ISSN database and monographs from WorldCat.