diff --git a/TLDs-compatibility.md b/TLDs-compatibility.md
index 8e26309..e36e86d 100644
--- a/TLDs-compatibility.md
+++ b/TLDs-compatibility.md
@@ -38,4 +38,8 @@ These TLDs are not working with an Mail-in-a-Box Standard-Setup because of Names
 ### Investigating
 Our Informations about these Domains are not sufficient. 
 
-* .adult.ht
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+* .adult.ht
+
+### Source
+
+Informations about these Domains are researched with the Reseller-Database of the **united-domains AG** in Starnberg, Germany. I do not guarantee for the correctness or timeliness of the information.
\ No newline at end of file