diff --git a/docs/basics/vpn-overview.md b/docs/basics/vpn-overview.md
index f8e41bb7..86fed668 100644
--- a/docs/basics/vpn-overview.md
+++ b/docs/basics/vpn-overview.md
@@ -73,4 +73,8 @@ By using a VPN with Tor, you're creating essentially a permanent entry node, oft
 
 Do not use that feature. The point of using Tor is that you do not trust your VPN provider. Currently Tor only supports the [TCP](https://en.wikipedia.org/wiki/Transmission_Control_Protocol) protocol. [UDP](https://en.wikipedia.org/wiki/User_Datagram_Protocol) (used in [WebRTC](https://en.wikipedia.org/wiki/WebRTC) for voice and video sharing, the new [HTTP3/QUIC](https://en.wikipedia.org/wiki/HTTP/3) protocol, etc.), [ICMP](https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol) and other packets will be dropped. To compensate for this, VPN providers typically will route all non-TCP packets through their VPN server (your first hop). This is the case with [ProtonVPN](https://protonvpn.com/support/tor-vpn/). Additionally, when using this Tor over VPN setup, you do not have control over other important Tor features such as [Isolated Destination Address](https://www.whonix.org/wiki/Stream_Isolation) (using a different Tor circuit for every domain you visit).
 
-The feature should be viewed as a convenient way to access the Tor Network, not to stay anonymous. For proper anonymity, use the Tor Browser, TorSocks, or a Tor gateway.
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+The feature should be viewed as a convenient way to access the Tor Network, not to stay anonymous. For proper anonymity, use the Tor Browser, TorSocks, or a Tor gateway.
+
+## Sources
+
+1. [VPN - a Very Precarious Narrative](https://schub.io/blog/2019/04/08/very-precarious-narrative.html) by Dennis Schubert
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