diff --git a/Detecting-changes-in-HTML-page-sources.md b/Detecting-changes-in-HTML-page-sources.md
index 86b6832..acb56bd 100644
--- a/Detecting-changes-in-HTML-page-sources.md
+++ b/Detecting-changes-in-HTML-page-sources.md
@@ -7,4 +7,6 @@ For example, the HTML response of web shops like https://www.campuspoint.de cont
 * In the General tab, prepend the target URL with `source:` (example: `source:https://www.campuspoint.de/mobile/notebooks/lenovo/thinkpad-t-serie/thinkpad-t14s.html`)
 * In the Request tab, choose the "Basic fast Plaintext/HTTP Client" fetch method
 * Choose a suitable trigger in the Filters & Triggers tab, for example the regex-based "Extract text" one.
-  * Example: use `/"product_count":(\d+)/i` to check when campuspoint.de adds new models of a certain laptop series to their inventory.
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+  * Example: use `/"product_count":(\d+)/i` to check when campuspoint.de adds new models of a certain laptop series to their inventory.
+
+more at https://changedetection.io/tutorial/source-code-monitor-how-get-alerts-changes-html-source-code
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