- Classification Web
Access by subscription to full-text display of all Library of Congress classification schedules—including G class geographic cutters. Offers full Library of Congress Subject Headings searching and mapping to LC classifications numbers.
- Dewey Decimal Classification Summaries
An introduction to Dewey Decimal Classification.
- Library of Congress Classification Outline
Covers the main classes of the Library of Congress Classification.
- Library of Congress Cutter Tables
This site includes the basic table and several specialized tables.
- Map Dewey (DDC) Classification to LC (LCC)
A table mapping Dewey Decimal Classifications to Library of Congress Class headings.
- Map LC (LCC) to Dewey (DDC) Classification
A table mapping Library of Congress Class headings to Dewey Decimal Classifications.
An OCLC online subscription service with two versions. You can subscribe to either the full (DDC 23) database, including Relative Index terms, built numbers not available in the print versions, and BISAC-to-DDC mappings; or to the Abridged Edition (14th, and soon, 15th editions), which is a condensed version of the DDC system for smaller libraries that covers all classes and key index terms.
- Classification and Shelflisting Manual. Washington, D.C.: Library of Congress, Cataloging Distribution Service, 2008–
- Dewey, Melvil. Abridged Dewey Decimal Classification and Relative Index. 14th ed. Eds. Joan S. Mitchell, et al. Dublin, Ohio: OCLC Online Computer Library Center, 2011.
- Dewey, Melvil. Dewey Decimal Classification and Relative Index. 23rd ed. Eds. Joan S. Mitchell, Julianne Beall, Rebecca Green, Giles Martin, Michael Panzer. 4 vols. Dublin, Ohio: OCLC Online Computer Library Center, 2011.