In 1968, the National Library published its first union list of serials, Periodicals in the Social Sciences and Humanities Currently Received by Canadian Libraries . Since 1980, all serially published government publications have also been included. Information on works in all languages is processed, provided that the catalogue record is in the Roman alphabet. Over 500 libraries' holdings are included in the online database. All types of libraries are represented, although academic libraries are by far the largest group.
Canadian libraries report their holdings in various ways.
During 1994-1995, serial holdings of some 21 Manitoba libraries were added online by staff located at the Manitoba Legislative Library. Retrospective conversion of the manual catalogue into the automated system would enable researchers to access information on Canadian holdings themselves, from anywhere in the country. The sheer size of the catalogue, the widely varying card formats and cataloguing styles, and the frequent repetition of titles, were all challenges that had to be met in attempting conversion. The project was carried out both by Library staff and by employees of three private-sector companies. Following the end of the project in March 1994, staff of the National Library reorganized the cards that had not been converted.