Pages are placed in this category when any of the following cite errors are generated on the page:

The named reference $1 was invoked but never defined (see the help page).

Please do not delete the ref nor comment it out. This error usually occurs because someone deleted another ref with that same name that had text in it. To fix these errors, look in the page history to find the deleted ref and copy its text into the remaining ref with the error message. To find the first entry of a ref use WikiBlame. AnomieBOT does some fixes and often leaves helpful suggestions on an article's Talk page.

Other reasons this error can occur:

The pages Template:Broken ref, Help:Cite errors and subpages contain deliberate errors and do not need to be repaired.

If you fix an error, you can leave this edit summary if you wish:
Fixed broken reference names – [[:Category:Pages with broken reference names|You can help!]]

Pages in this category are sorted by namespace; articles are sorted by their first letter (A-Z), and pages in other namespaces are sorted using Greek letters so that they are listed after all of the articles.