diff --git a/src/core/res_intf.ml b/src/core/res_intf.ml
index 20b689f1..5b443bd0 100644
--- a/src/core/res_intf.ml
+++ b/src/core/res_intf.ml
@@ -76,19 +76,19 @@ module type S = sig
 
   (** {3 Proof Nodes} *)
 
+  val parents : step -> proof list
+  (** Returns the parents of a proof node. *)
+
   val is_leaf : step -> bool
   (** Returns wether the the proof node is a leaf, i.e. an hypothesis,
       an assumption, or a lemma.
-      [true] if and only if {parents} returns the empty list. *)
+      [true] if and only if {!parents} returns the empty list. *)
 
   val expl : step -> string
   (** Returns a short string description for the proof step; for instance
       ["hypothesis"] for a [Hypothesis]
       (it currently returns the variant name in lowercase). *)
 
-  val parents : step -> proof list
-  (** Returns the parents of a proof node. *)
-
 
   (** {3 Proof Manipulation} *)