diff --git a/Advanced-Content-Filter-addon.md b/Advanced-Content-Filter-addon.md
index 65cee13..2aa0706 100644
--- a/Advanced-Content-Filter-addon.md
+++ b/Advanced-Content-Filter-addon.md
@@ -23,6 +23,6 @@ I want to filter all those news pages and luckily a lot of them contain the word
 
 ## 4. Collapse all posts _not_ from a specific account
 
-`author_link != 'https://friendica.example.tld/profile/username && body matches "/blubb/"`
+`author_link != 'https://friendica.example.tld/profile/username' && body matches "/blubb/"`
 
 This rule matches items that have the word `blubb` in their body and which were not published by the profile `https://friendica.example.tld/profile/username`. Remember that equality operators `==` and `!=` match the exact string against the provided item property, while `matches` that can match a portion of the item property.
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