diff --git a/msx/README.md b/msx/README.md
index 95a5849..ecbdcfa 100644
--- a/msx/README.md
+++ b/msx/README.md
@@ -1,5 +1,10 @@
 MSX character sets
 ==================
 
-These character sets were all obtained from the blueMSX emulator at bluemsx.com
-The MSX DIN character set is derived from the default western MSX charset as described in https://www.msx.org/wiki/MSX_font
+These character sets were extracted from various MSX ROM dumps. The character mappings are based on those distributed with Unicode 
+proposal L2/21-235 [Proposal to add further characters from legacy computers and teletext to the UCS](https://www.unicode.org/L2/L2021/21235-terminals-supplement.pdf)
+
+References:
+- https://www.msx.org/wiki/MSX_font
+- https://www.msx.org/forum/msx-talk/general-discussion/msx-character-set-unicode-help-needed
+- http://bluemsx.msxblue.com/download.html