diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+1.6.1 (2024-10)
+-------------
+
+* Fixed an issue where `Control.DeepSeq.Unit`, exported as of version 1.5.1.0, conflicts with `Numeric.Units.Dimensional.Unit` (#228).
+* Fixed broken links to the Tau and Pi manifestos (#229).
+
 1.6 (2024-08)
 -------------
 
diff --git a/dimensional.cabal b/dimensional.cabal
--- a/dimensional.cabal
+++ b/dimensional.cabal
@@ -1,5 +1,5 @@
 name:                dimensional
-version:             1.6
+version:             1.6.1
 license:             BSD3
 license-file:        LICENSE
 copyright:           Bjorn Buckwalter 2006-2024
diff --git a/src/Numeric/Units/Dimensional/Dimensions/TermLevel.hs b/src/Numeric/Units/Dimensional/Dimensions/TermLevel.hs
--- a/src/Numeric/Units/Dimensional/Dimensions/TermLevel.hs
+++ b/src/Numeric/Units/Dimensional/Dimensions/TermLevel.hs
@@ -36,7 +36,7 @@
 )
 where
 
-import Control.DeepSeq
+import Control.DeepSeq (NFData(..))
 #if USE_BINARY
 import qualified Data.Binary
 #endif
diff --git a/src/Numeric/Units/Dimensional/Dynamic.hs b/src/Numeric/Units/Dimensional/Dynamic.hs
--- a/src/Numeric/Units/Dimensional/Dynamic.hs
+++ b/src/Numeric/Units/Dimensional/Dynamic.hs
@@ -36,7 +36,7 @@
 , (*), (/), (^), recip, applyPrefix
 ) where
 
-import Control.DeepSeq
+import Control.DeepSeq (NFData)
 import Control.Monad
 #if USE_BINARY
 import qualified Data.Binary
diff --git a/src/Numeric/Units/Dimensional/FixedPoint.hs b/src/Numeric/Units/Dimensional/FixedPoint.hs
--- a/src/Numeric/Units/Dimensional/FixedPoint.hs
+++ b/src/Numeric/Units/Dimensional/FixedPoint.hs
@@ -342,8 +342,8 @@
 
 -- | Twice 'pi'.
 --
--- For background on 'tau' see https://tauday.com/tau-manifesto (but also
--- feel free to review https://web.archive.org/web/20200926221249/http://www.thepimanifesto.com/).
+-- For background on 'tau' see [The Tau Manifesto](https://tauday.com/tau-manifesto) (but also
+-- feel free to review [The Pi Manifesto](https://web.archive.org/web/20200926221249/http://www.thepimanifesto.com/)).
 tau :: (Integral a, E.KnownExactPi s) => SQuantity s DOne a
 tau = rescale (epsilon :: SQuantity (E.ExactNatural 2 E.* E.Pi) DOne Integer)
 
diff --git a/src/Numeric/Units/Dimensional/Internal.hs b/src/Numeric/Units/Dimensional/Internal.hs
--- a/src/Numeric/Units/Dimensional/Internal.hs
+++ b/src/Numeric/Units/Dimensional/Internal.hs
@@ -26,7 +26,7 @@
 where
 
 import Control.Applicative
-import Control.DeepSeq
+import Control.DeepSeq (NFData)
 import Data.AEq (AEq)
 #if USE_BINARY
 import qualified Data.Binary
diff --git a/src/Numeric/Units/Dimensional/UnitNames/InterchangeNames.hs b/src/Numeric/Units/Dimensional/UnitNames/InterchangeNames.hs
--- a/src/Numeric/Units/Dimensional/UnitNames/InterchangeNames.hs
+++ b/src/Numeric/Units/Dimensional/UnitNames/InterchangeNames.hs
@@ -9,7 +9,7 @@
 )
 where
 
-import Control.DeepSeq
+import Control.DeepSeq (NFData)
 import Data.Data
 import GHC.Generics
 import Prelude
diff --git a/src/Numeric/Units/Dimensional/UnitNames/Internal.hs b/src/Numeric/Units/Dimensional/UnitNames/Internal.hs
--- a/src/Numeric/Units/Dimensional/UnitNames/Internal.hs
+++ b/src/Numeric/Units/Dimensional/UnitNames/Internal.hs
@@ -14,7 +14,7 @@
 module Numeric.Units.Dimensional.UnitNames.Internal
 where
 
-import Control.DeepSeq
+import Control.DeepSeq (NFData(..))
 import Control.Monad (join)
 import Data.Coerce
 import Data.Data hiding (Prefix)
diff --git a/src/Numeric/Units/Dimensional/Variants.hs b/src/Numeric/Units/Dimensional/Variants.hs
--- a/src/Numeric/Units/Dimensional/Variants.hs
+++ b/src/Numeric/Units/Dimensional/Variants.hs
@@ -28,7 +28,7 @@
 )
 where
 
-import Control.DeepSeq
+import Control.DeepSeq (NFData)
 import Data.Data
 import qualified Data.ExactPi.TypeLevel as E
 import GHC.Generics