diff --git a/README.md b/README.md
index 07d0ba0..2f868fc 100644
--- a/README.md
+++ b/README.md
@@ -26,15 +26,16 @@ will suffice.
 The compilation requirements are:
 
 * a recent version of ocaml (at  least 4.02)
+* containers (https://github.com/c-cube/ocaml-containers)
 * xmlm (http://erratique.ch/software/xmlm)
-* kaputt (http://kaputt.x9c.fr)
+* kaputt (http://kaputt.x9c.fr) (optional)
 * oasis (http://oasis.forge.ocamlcore.org)
 * result (if you are running ocaml < 4.03 )
 * sexplib
 
 The easiest way to install them is via opam (https://opam.ocaml.org):
 
-opam install oasis xmlm kaputt result sexplib
+opam install containers oasis xmlm kaputt result sexplib
 
 To initialize the configuration, call
 
diff --git a/src/arg_handler.ml b/src/arg_handler.ml
index 1103367..f211a8f 100644
--- a/src/arg_handler.ml
+++ b/src/arg_handler.ml
@@ -86,8 +86,8 @@ let handlers s =
   ]
 
 let use_string =
-  ("usage: tlapm [-fingerprints] [-xml-input] [-with-java path]" ^
-   "[-check-schema] [-toolbox from to] input_file")
+  ("usage: tlapm [--fingerprints] [--xml-input] [--with-java path]" ^
+   "[--check-schema] [--toolbox from to] input_file")
 
 let handle_arguments argv =
   let s = { settings = default_settings } in