diff --git a/specs/v1.5/spec.md b/specs/v1.5/spec.md
index e1a5b8d..5910268 100644
--- a/specs/v1.5/spec.md
+++ b/specs/v1.5/spec.md
@@ -54,7 +54,7 @@ After successfully finding the *target user* through a hub, the user can generat
 
 [SMP][smp-wiki] protocol allows two entities to compare if their secrets are the same or not, without revealing other information.
 
-We modified the ECC based SMP protocol from [OTR v4][otr-spec-v4] for performance purpose. Baby Jubjub and Poseidon hash are used due to their efficiency in zk-SNARK, instead of the original Ed448 with SHAKE-256. The following contents are largely referenced from [maci-crypto](https://github.com/appliedzkp/maci/blob/master/crypto/ts/index.ts) and [baby-jubjub](https://github.com/iden3/circomlib/blob/master/src/babyjub.js#L21).
+We modified the ECC based SMP protocol from [OTR v4][otr-spec-v4] for performance purpose. Baby Jubjub and Poseidon hash are used due to their efficiency in zk-SNARK, instead of the original Ed448 with SHAKE-256. The following contents are largely referenced from [maci-crypto](https://github.com/appliedzkp/maci/blob/master/crypto/ts/index.ts) and [baby-jubjub](https://github.com/iden3/circomlibjs/blob/main/src/babyjub.js#L8).
 
 ### Constants
 ```typescript