diff --git a/TODO b/TODO
index bf637c4..8fb68a2 100755
--- a/TODO
+++ b/TODO
@@ -1,22 +1,18 @@
-* i18n
+* i18n : i18n of errors in index.php and use a different template for each translation
+* Don't cache the username
+* JSON output
 
 inc/Invoices.class.php :
 ========================
-* Storage ?
-* Modify load() method to handle complex queries (such as WHERE date < DATE_1 AND date > DATE_2)
-
-==========
-* Don't cache the username
-==========
+* Storage of users in ?!?
 
 Manage paybacks :
 =================
-* TODO : Payback system
+* TODO : Payback system (class should be ok)
 
 TODO :
 ======
 * Add / Edit a bill
-* JSON output
 
 To test :
 =========
diff --git a/inc/Invoices.class.php b/inc/Invoices.class.php
index 665f902..a2c1661 100644
--- a/inc/Invoices.class.php
+++ b/inc/Invoices.class.php
@@ -1,10 +1,11 @@
 <?php
+    // TODO : Handle users_in
     require_once('data/config.php');
     require_once('Storage.class.php');
+    require_once('UsersIn.class.php');
 
     class Invoice extends Storage {
         protected $id = 0, $date, $users_in, $guests, $buyer, $amount, $what;
-        // users_in is an array of user ids
         // date is a DateTime object
         // buyer is a User object
         // guests is an array with same keys as users_in
@@ -12,13 +13,13 @@
         protected $fields = array(
             'id'=>'key',
             'date'=>'date',
-            'users_in'=>'string', // TODO
             'buyer'=>'int',
             'amount'=>'float',
             'what'=>'text'
             );
 
         public function __construct() {
+            $users_in = new UsersIn();
             parent::__construct();
         }
 
@@ -32,10 +33,6 @@
             return $this->date->format($format);
         }
 
-        public function getUsersIn() {
-            return $this->users_in;
-        }
-
         public function getGuests() {
             return $this->guests;
         }
@@ -64,10 +61,6 @@
             $this->date = DateTime::createFromFormat('Y-n-j G:i', $year.'-'.(int) $month.'-'.(int) $day.' '.(int) $hour.':'.$minute);
         }
 
-        public function setUsersIn($users_in) {
-            $this->users_in = $users_in;
-        }
-
         public function setGuests($guests) {
             $this->guests = $guests;
         }
@@ -91,7 +84,6 @@
             $this->what = htmlspecialchars($this->what);
             $this->amount = (float) $this->amount;
             $this->buyer = (int) $this->buyer;
-            $this->users_in = htmlspecialchars($this->users_in);
             $this->date = htmlspecialchars($this->date);
 
             return $this;
@@ -108,7 +100,6 @@
             $this->setWhat($data['what']);
             $this->setAmount($data['amount']);
             $this->setBuyer($data['buyer']);
-            $this->setUsersIn($data['users_in']);
             $this->setDate($data['date']);
         }
     }
diff --git a/inc/Storage.class.php b/inc/Storage.class.php
index 1dbd5f4..bd8f193 100644
--- a/inc/Storage.class.php
+++ b/inc/Storage.class.php
@@ -116,7 +116,23 @@ class Storage {
             foreach($fields as $field=>$value) {
                 if($i) { $query .= ' WHERE '; $i = false; } else { $query .= ' AND ';  }
 
-                $query .= $field.'=:'.$field;
+                if(!is_array($value)) {
+                    $value = array($value);
+                }
+
+                foreach($value as $value_array) {
+                    if($value_array == 'AND' || $value_array = 'OR') {
+                        $query .= ' '.$value_array.' ';
+                        continue;
+                    }
+
+                    if(substr($value_array, 0, 1) == "<")
+                        $query .= $field.'<:'.$field;
+                    elseif(substr($value_array, 0, 1) == ">")
+                        $query .= $field.'>:'.$field;
+                    else
+                        $query .= $field.'=:'.$field;
+                }
             }
         }
 
@@ -124,10 +140,21 @@ class Storage {
 
         if(!empty($fields) && is_array($fields)) {
             foreach($fields as $field=>$value) {
+                if(!is_array($value))
+                    $value = array($value);
+
                 if($fields[$field] == 'date')
                     $value = $value->format('Y-m-d H:i:s');
 
-                $query->bindParam(':'.$field, $value);
+                foreach($value as $value_array) {
+                    if($value_array == 'AND' || $value_array == 'OR')
+                        continue;
+
+                    if(substr($value, 0, 1) == ">" || substr($value, 0, 1) == "<")
+                        $query->bindParam(':'.$field, substr($value, 0, 1);
+                    else
+                        $query->bindParam(':'.$field, $value);
+                }
             }
         }