diff --git a/hq.cabal b/hq.cabal
--- a/hq.cabal
+++ b/hq.cabal
@@ -7,7 +7,7 @@
 -- hash: ccfecaab3d1004f03e5a9e851269c0209561044c1b9aa90d587dc93a936394f0
 
 name:           hq
-version:        0.1.0.3
+version:        0.1.0.4
 synopsis:       Quantitative Library
 category:       Finance
 description:    Please see the README on GitHub at <https://github.com/ghais/hq#readme>
@@ -22,9 +22,6 @@
 extra-source-files:
     README.md
     ChangeLog.md
-flag onlygsl
-    description:    don't link gslcblas
-    default:        False
 
 flag disable-default-paths
     description:    When enabled, don't add default hardcoded include/link dirs by default. Needed for hermetic builds like in nix.
@@ -157,10 +154,7 @@
         if arch(x86_64)
             cc-options: -fPIC
 
-  if flag(onlygsl)
-      extra-libraries: gsl
-  else
-      pkgconfig-depends: gsl  
+  pkgconfig-depends: gsl  
 
 test-suite bachelier-test
   default-extensions:
diff --git a/src/Q/Options/ImpliedVol/StrikeInterpolation.hs b/src/Q/Options/ImpliedVol/StrikeInterpolation.hs
--- a/src/Q/Options/ImpliedVol/StrikeInterpolation.hs
+++ b/src/Q/Options/ImpliedVol/StrikeInterpolation.hs
@@ -26,6 +26,9 @@
   interpolateV CubicAkima    (SortedVector strikes) vols (Strike k) =
     Vol $ GSL.evaluateV GSL.Akima  (coerce strikes) (coerce vols) k
 
+
   interpolateV CubicMonotone (SortedVector strikes) vols (Strike k) =
-    Vol $ GSL.evaluateV GSL.Steffen (coerce strikes) (coerce vols) k
+    -- The interpolation method should be Steffen but until the next
+    -- version of hmatrix-gsl is release i am using Akima.
+    Vol $ GSL.evaluateV GSL.Akima (coerce strikes) (coerce vols) k