diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+pandoc-citeproc (0.7.1.1)
+
+  * Fixed regression in numerical citation collapsing (#131).
+
 pandoc-citeproc (0.7.1)
 
   * Improvements to numerical styles:
diff --git a/pandoc-citeproc.cabal b/pandoc-citeproc.cabal
--- a/pandoc-citeproc.cabal
+++ b/pandoc-citeproc.cabal
@@ -1,5 +1,5 @@
 name:               pandoc-citeproc
-version:            0.7.1
+version:            0.7.1.1
 cabal-version:      >= 1.12
 synopsis:           Supports using pandoc with citeproc
 
diff --git a/src/Text/CSL/Proc/Collapse.hs b/src/Text/CSL/Proc/Collapse.hs
--- a/src/Text/CSL/Proc/Collapse.hs
+++ b/src/Text/CSL/Proc/Collapse.hs
@@ -59,8 +59,9 @@
       numOf  = foldr (\x _ -> x) 0 . citNums
       process xs = if hasLocator xs
                       then xs
-                      else let ys = concat (groupConsecWith numOf xs)
-                           in if length ys > 2
+                      else flip concatMap (groupConsecWith numOf xs)
+                           $ \ys ->
+                              if length ys > 2
                                  then [ Output [
                                             head ys
                                           , OPan [Str "\x2013"]