diff --git a/lib/jormungandr/src/Cardano/Wallet/Jormungandr/Transaction.hs b/lib/jormungandr/src/Cardano/Wallet/Jormungandr/Transaction.hs
index ac9e252b50b..44de2a1dbf1 100644
--- a/lib/jormungandr/src/Cardano/Wallet/Jormungandr/Transaction.hs
+++ b/lib/jormungandr/src/Cardano/Wallet/Jormungandr/Transaction.hs
@@ -45,9 +45,11 @@ newTransactionLayer block0Hash = TransactionLayer
     withEither :: e -> Maybe a -> Either e a
     withEither e = maybe (Left e) Right
 
-
 newtype WitnessData = WitnessData ByteString
 
+-- Rust implementation:
+--
+-- https://github.com/input-output-hk/rust-cardano/blob/13af7aa08cdac8efc9dc8b0f7ff9162d28b2d479/chain-impl-mockchain/src/transaction/witness.rs#L60-L61
 witnessUtxoData :: Hash "Block0Hash" -> Hash "Tx" -> WitnessData
 witnessUtxoData (Hash block0) (Hash tx) = WitnessData (block0 <> tx)