The Science Fiction, Fantasy, & Weird Fiction Magazine Index (1999 edition, 2008 edition) is a comprehensive database compiled by Stephen T. Miller and William G. Contento. It is published by Locus Press on a CD-ROM and indexes 1,100 titles, 16,200 issues, 26,700 authors and 105,900 stories (2008 release).
The Locus Magazine website includes a Checklist of magazine titles and issues which are indexed in the 2006 release. When verifying records on the ISFDB giving "Miller/Contento" as a source, you're indicating that the record is verified with the database's record and not the online checklist.
Here is a checklist created from the 2008 CD-ROM edition.