diff --git a/src/Nethermind/Nethermind.Crypto/BlsSigner.cs b/src/Nethermind/Nethermind.Crypto/BlsSigner.cs
index 3711a2be364..f0c4d672c7f 100644
--- a/src/Nethermind/Nethermind.Crypto/BlsSigner.cs
+++ b/src/Nethermind/Nethermind.Crypto/BlsSigner.cs
@@ -8,6 +8,8 @@
 
 namespace Nethermind.Crypto;
 
+// https://www.ietf.org/archive/id/draft-irtf-cfrg-bls-signature-05.html
+
 using G1 = Bls.P1;
 using G1Affine = Bls.P1Affine;
 using G2 = Bls.P2;