Template:Please check ISSN/doc

Usage
This template is used to mark an International Standard Serial Number (ISSN) that may not be valid. For example:

The template does not produce any visible change to the article (unless the article is viewed in preview mode):

Rather, it adds the article to the hidden maintenance/tracking category: Category:Articles with invalid ISSNs.

In preview mode, it shows the warning message (Warning: Check ISSN). This warning is shown only in preview mode.

Parameters
The optional parameter reason simply provides a comment to explain why the ISSN may not be valid. For example: