diff --git a/lib/STM_internal.ml b/lib/STM_internal.ml
index cd2e7cb74..d25d1ef36 100644
--- a/lib/STM_internal.ml
+++ b/lib/STM_internal.ml
@@ -156,8 +156,8 @@ module Make(Spec : STM_spec.Spec) = struct
       (fun (seq,p1,p2) -> all_interleavings_ok seq p1 p2 Spec.init_state)
       (fun ((seq,p1,p2) as triple) ->
         (* Shrinking heuristic:
-          First reduce the cmd list sizes as much as possible, since the interleaving
-          is most costly over long cmd lists. *)
+           First reduce the cmd list sizes as much as possible, since the interleaving
+           is most costly over long cmd lists. *)
         (map (fun seq' -> (seq',p1,p2)) (Shrink.list_spine seq))
         <+>
         (match p1 with [] -> Iter.empty | c1::c1s -> Iter.return (seq@[c1],c1s,p2))
diff --git a/lib/STM_spec.mli b/lib/STM_spec.mli
index cb9a189c5..2dd83b0f1 100644
--- a/lib/STM_spec.mli
+++ b/lib/STM_spec.mli
@@ -97,8 +97,8 @@ sig
 
   val next_state : cmd -> state -> state
   (** [next_state c s] expresses how interpreting the command [c] moves the
-      model's internal state machine from the state [s] to the next state.
-      Ideally a [next_state] function is pure. *)
+      model's internal state machine from the state [s] to the next state.
+      Ideally a [next_state] function is pure. *)
 
   val init_sut : unit -> sut
   (** Initialize the system under test. *)