Skip to Main Content

Chicago Manual of Style (COMS) Guide - 18th Edition

This guide provides the basic citation guidance and examples based on the Chicago Manual of Style 18th Edition..

What’s New in the 18th Edition

This document, from the COMS 18th Edition Blog, lists all the changes and clarification in the new edition. Below are listed the most important changes and clarifications related to source citations with active links to the appropriate sections in COMS Online.

Most Important Changes in Source Citations

Note: All Paragraph and section numbers refer to the print and online versions of the 18th Edition. All of the links go directly to the Online Version.

Part III: SOURCE CITATIONS AND INDEXES

Chapter 13: Source Citations: Overview 

  • Source with Multiple Authors - Up to six authors are now listed in a bibliography or reference list entry; if more than six, only the first three are listed, followed by “et al.” In a shortened note or an author-date text citation, up to two authors are now listed; if more than two, only the first is listed, followed by “et al.” - See 13.23 -- Notes and Bibliography or 13.107 - Author-Date 
     
  • Journal Article Dates - Only include the publication year, a month or season can now usually be omitted in citations of journal articles. See 13.26
     
  • The 3-em Dash - Repeat the name of the author(s) rather than using a 3-em dash to stand in for repeated names in bibliographies or reference lists. See 13.72 -- Notes and Bibliography or 13.113 -- Author-Date 
     
  • Ibid -  Shortened citations used instead of “ibid.” may take one of three forms: author-title (Chicago’s regular short form), author-only, or title-only. See 13.37 
     
  • Mentioning vs. Citing Sources - See new guidance on the difference between mentioning sources and citing them. See 13.5 
     
  • Shortened URLs -- See expanded guidance on using shortened URLs in citations. See 13.11

​​​​​​​Chapter 14: Source Citations: Examples

  • Page Range in an Edited Book - The page range for a cited chapter in an edited book is no longer required in a bibliography or reference list entry (though a page range is still required for most journal articles). See 14.8
     
  • Place of Publication for Books - A place of publication is no longer required in citations of books. See 14.30
     
  • ​​​​​​​Citing an Illustrator - See new guidance on citing an editor, translator or illustrator in addition to an author. See 14.6
     
  • Citing Forthcoming Journals Articles - See updated and expanded guidance on citing ahead-of-print and forthcoming journal articles. See 14.75 and 14.76
     
  • Citing AL Generated Content - See new guidance on citing AI-generated content. See 14.112
     
  • Citing Indigenous Sources - See new guidance on citing Indigenous sources. See 14.136 and 14.137
     
  • Citing Databases and Datasets - See Updated and expanded guidance on citing databases and datasets. See 14.157