diff --git a/README b/README
index ce41d19..cddf485 100644
--- a/README
+++ b/README
@@ -75,7 +75,7 @@ The following tools are implemented:
 =*|x sha256sum   .
 =*|x sha512sum   .
 =*|o sleep       .
-#*|o sort        (-d, -f, -i)
+#*|o sort        .
 =*|o split       .
 =*|x sponge      .
 #*|o strings     .
diff --git a/sort.1 b/sort.1
index 52c73dc..bfdce6c 100644
--- a/sort.1
+++ b/sort.1
@@ -92,3 +92,9 @@ as the field delimiter.
 .It Fl u
 Print equal lines only once.
 .El
+.Sh STANDARDS
+The
+.Nm
+utility is compliant with the
+.St -p1003.1-2013
+specification.