Cataloging is a highly detailed task that often requires selecting the correct option from a list. Catalogers usually have to consult various resources in order to catalog something correctly. This guide contains some resources you may find helpful.
Some libraries use OCLC as their source for already created bibliographic records and to create new ones to add to the incredibly large pool of bib records that OCLC has. Other, smaller libraries, may not use OCLC and get their bib records from other sources, or create all their own records for inclusion into their online catalog.
Bibliographic records can be in different formats, but the most common one is MARC format.
Many of these resources and programs are funded under the provisions of the Library Services and Technology Act from the Institute of Museum and Library Services.