diff --git a/infrastructure/acme.md b/infrastructure/acme.md
index 929f431..ef8357f 100644
--- a/infrastructure/acme.md
+++ b/infrastructure/acme.md
@@ -10,6 +10,18 @@ We agreed to use **ACME DNS-01 challenges** for issuing certificates for **both
 - Keep **low TTLs** (e.g., 60-120s) on both CNAME and TXT records to speed up renewals.
 - Restrict write access to the challenge zone to the ACME automation only.
 
+## Meetings
+- 05.08.2025: Bert-Jan Fikse, Tobias Schaller, Tobias Wüst, Tom Jampen (inital version)
+
+## Background
+The following article explains how DNS-01 challenges can be effectively used to issue Let's Encrypt certificates for servers with internal IP addresses:
+
+- https://lists.bfh.science/pipermail/bfh-linux-announce/2021-September/000134.html
+
+The following manpage explains important implementation details for correctly handling DNS-01 challenges:
+
+- https://sources.debian.org/src/open-infrastructure-service-tools/20250626-2/dehydrated/share/man/dehydrated-nsupdate.1.rst#L20
+
 ## Reference Design
 **Dedicated zone:**
 `_acme.digitalboard.ch`