diff --git a/s390x.md b/s390x.md
index 326904b..0c0e8ca 100644
--- a/s390x.md
+++ b/s390x.md
@@ -8,6 +8,7 @@
 - [SWLUG Talk - Linux on the IBM Z mainframe platform](https://www.youtube.com/watch?v=V-5dqnTd09k)
 - https://wiki.qemu.org/Documentation/Platforms/S390X
 - https://arstechnica.com/information-technology/2023/07/the-ibm-mainframe-how-it-runs-and-why-it-survives/
+- https://sdl-hercules-390.github.io/html/
 
 ## From xet7, other non-WeKan Open Source at s390x