diff --git a/crdt.cabal b/crdt.cabal
--- a/crdt.cabal
+++ b/crdt.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 23bb86a0781bcb24463115698ce7fa54478558dc1e341c509ce2db3b2f5a71d7
+-- hash: 7021f3e0d6e0f14ccbff42fd8252b25b479ffd645160458d77d1c854912c9698
 
 name:           crdt
-version:        6.1
+version:        6.2
 synopsis:       Conflict-free replicated data types
 description:    Definitions of CmRDT and CvRDT. Implementations for some classic CRDTs.
 category:       Distributed Systems
diff --git a/lib/CRDT/LamportClock.hs b/lib/CRDT/LamportClock.hs
--- a/lib/CRDT/LamportClock.hs
+++ b/lib/CRDT/LamportClock.hs
@@ -33,7 +33,6 @@
 import           Data.Time.Clock.POSIX (getPOSIXTime)
 import           Data.Word (Word64)
 import           Network.Info (MAC (MAC), getNetworkInterfaces, mac)
-import           Numeric (showHex)
 import           Numeric.Natural (Natural)
 import           Safe (headDef)
 
@@ -41,10 +40,7 @@
 type LocalTime = Natural
 
 data LamportTime = LamportTime !LocalTime !Pid
-    deriving (Eq, Ord)
-
-instance Show LamportTime where
-    show (LamportTime time (Pid pid)) = showHex time "" ++ '-' : showHex pid ""
+    deriving (Eq, Ord, Show)
 
 -- | Unique process identifier
 newtype Pid = Pid Word64
@@ -134,3 +130,10 @@
                 pure time1
             pid <- getPidByMac
             pure $ LamportTime time1 pid
+
+instance Process m => Process (ReaderT r m) where
+    getPid = lift getPid
+
+instance Clock m => Clock (ReaderT r m) where
+    advance = lift . advance
+    getTime = lift getTime