diff --git a/graphs/graphs.ms b/graphs/graphs.ms
index f08388e..28a98cd 100644
--- a/graphs/graphs.ms
+++ b/graphs/graphs.ms
@@ -1,4 +1,21 @@
 .so macros.roff
+.de TREE1
+.QP
+.KS
+.ft CW
+.b1
+.nf
+..
+.de TREE2
+.ft
+.fi
+.b2
+.KE
+.QE
+..
+.
+. \" The document starts here.
+.
 .TITLE Document Oriented DataBase (DODB)
 .AUTHOR Philippe P.
 .ABSTRACT1
@@ -156,15 +173,13 @@ Let's create a DODB database for our cars.
 db = DODB::DataBase(Car).new "path/to/db-cars"
 
 # Adding an element to the db
-db << Car.new "Corvet GT", "red", ["elegant", "fast"]
+db << Car.new "Corvet", "red", ["elegant", "fast"]
 
 # Reaching all objects in the db
 db.each do |car|
 	pp! car
 end
 .SOURCE
-
-.SS Storing data
 When a value is added, it is serialized\*[*] and written in a dedicated file.
 .FOOTNOTE1
 Serialization is currently in JSON.
@@ -172,32 +187,30 @@ CBOR is a work-in-progress.
 Nothing binds DODB to a particular format.
 .FOOTNOTE2
 The key of the hash is a number, auto-incremented, used as the name of the stored file.
-The following example shows the content of the file system after adding three values.
-.de TREE1
-.QP
-.KS
-.ft CW
-.b1
-.nf
-..
-.de TREE2
-.ft
-.fi
-.b2
-.KE
-.QE
-..
+The following example shows the content of the file system after adding the first car.
 .TREE1
-$ tree storage/
-storage
-`-- data
-     +-- 0000000000
-     +-- 0000000001
-     `-- 0000000002
+$ tree db-cars/
+db-cars/
+|-- data
+|   `-- 0000000000   <- the first car in the database
+`-- last-index
 .TREE2
 In this example, the directory
-.I storage/data
-contains all three serialized values, with a formated number as their file name.
+.I db-cars/data
+contains the serialized value, with a formated number as file name.
+The file "0000000000" contains the following:
+.QP
+.SOURCE JSON ps=10
+{
+  "name": "Corvet",
+  "color": "red",
+  "keywords": [
+    "elegant",
+    "fast"
+  ]
+}
+.SOURCE
+.QE
 .SS Indexes
 Database entries can be
 .I indexed