Compilations:

Items are edited together into single volumes.

Dictionaries:

Subject-specific dictionaries exist for a variety of topics.

Directories:

A book containing one or more alphabetical lists of the inhabitants of any locality, with their addresses and occupations; also a similar compilation dealing with the members of a particular profession, trade, or association, for example a Clerical or Medical Dictionary, etc. 

Encyclopedias

Guides:

• Archives and Manuscripts
• Audiovisual
• Databases
• General
• Patents

Handbooks

Patent and Statistical Databases

1. Patents
2. Statistics
3. Reference

Technical Surveys and Reports

1. Archives
2. Audiovisual
3. Copyright
4. General

Thesauri -- Classified list of terms or keywords

1. Archives
2. Art and Architecture
3. Classical Languages
4. Cultures, Anthropology, and Sociology
5. General
6. Law and Politics
7. Museology
8. Music
9. Science and Mathematics

Union Catalogs

National Union Catalog is an example. Another example is OCLC Worldcat.

UNT Primary Resources

• Digital Collections

  The UNT Digital Library is a centralized repository for the rich collections held by the libraries, colleges, schools, and departments at the University of North Texas

• The Portal to Texas History

  A gateway to rare, historical, and primary source materials from or about Texas.

• UNT Libraries: Finding Aids

  Use this tool to browse descriptions of our unique holdings. You can request these items to be viewed in the Special Collections Reading room on Willis Library's 4th Floor.

• Library of Congress

  Primary Source Sets