Go to Admin > Publishing > Folders

Right Click on the article and select the Restrict Access option

Select the Security you wish to access the article and Click Save.

If none selected then it will be viewed by all because it is in a public folder.

Using this option you can restrict access to a particular article – but the article needs to be in a public folder. If the

article is in a private folder then you cannot use the restrict access option on an article.

Note: This will only affect the viewing of the article, not the security for updating an article.