RLIN 21 Searching
RLIN21 is the interface to the Research Libraries Group (RLG) Union Catalog, containing millions of bibliographic records for many different media. It serves Technical Services as a means of verifying bibliographic information and as a source for record import into Voyager.
There is copious searching documentation available at the RLG web site.
Read also An introduction to MARC if you are unfamiliar with the MRC format. This will help you understand the RLIN displays and the information contained in them.