diff --git a/README b/README
index f70d485..ee48598 100644
--- a/README
+++ b/README
@@ -11,3 +11,22 @@ and from mobile phone. Currently supported networks:
 
 USE AT YOUR OWN RISK!
 
+
+Acknowledgements:
+
+Hans Wigger for providing valuable informations about A-Netz and B-Netz.
+
+Stephan Hessberger for his work on oebl.de, that provides valuable informations
+about A-Netz, B-Netz and C-Netz.
+
+Friedhelm Hillebrand for providing complete specification for mobile phone of
+C-Netz.
+
+Klaus Adler for helping me to retrieve complete NMT specification back in the
+90's.
+
+Andy Zauner for providing me signalling specification of C-Netz back in the
+90's.
+
+Carsten Wollesen for donating Telefunken 4015 B-Netz phone back in the 90's.
+