diff --git a/doc/erko_howto_tools.txt b/doc/erko_howto_tools.txt
index bf0f713aa0b0599abdb647777b39ccb1c99e321d..3bd3a1be0d91ba3f973f5aedc3f7fe47fbd0b994 100755
--- a/doc/erko_howto_tools.txt
+++ b/doc/erko_howto_tools.txt
@@ -132,6 +132,8 @@ https://git.astron.nl/desp/hdl/-/blob/L2SDP-36/libraries/technology/ip_arria10_e
 * ARGS
 *******************************************************************************
 
+Alternative: SystemRDL ?
+
 1) Synthesis flow
 cd ~/git/hdl
 . ./init_hdl.sh
@@ -408,6 +410,7 @@ https://git.astron.nl/desp/args/-/blob/master/Markdown/readme_markdown.txt
 
 Official guide: https://daringfireball.net/projects/markdown/syntax
 
+https://www.markdownguide.org/basic-syntax/
 
 *******************************************************************************
 * vi