diff --git a/Document.php b/Document.php
index 7803df6..0e920fd 100644
--- a/Document.php
+++ b/Document.php
@@ -1,49 +1,108 @@
 <?php
-class Document {
-
-    public $user;
-
-    public $name;
-
-    public function init($name, User $user) {
-        assert(strlen($name) > 5);
-        $this->user = $user;
-        $this->name = $name;
-    }
-
-    public function getTitle() {
-        $db = Database::getInstance();
-        $row = $db->query('SELECT * FROM document WHERE name = "' . $this->name . '" LIMIT 1');
-        return $row[3]; // third column in a row
-    }
-
-    public function getContent() {
-        $db = Database::getInstance();
-        $row = $db->query('SELECT * FROM document WHERE name = "' . $this->name . '" LIMIT 1');
-        return $row[6]; // sixth column in a row
-    }
-
-    public static function getAllDocuments() {
-        // to be implemented later
-    }
-
-}
-
-class User {
-
-    public function makeNewDocument($name) {
-        $doc = new Document();
-        $doc->init($name, $this);
-        return $doc;
-    }
-
-    public function getMyDocuments() {
-        $list = array();
-        foreach (Document::getAllDocuments() as $doc) {
-            if ($doc->user == $this)
-                $list[] = $doc;
+  
+  class Document {
+    
+    protected $user, $name;
+    protected static $db;
+    
+    public function __construct( $name, User $user ) {
+      assert( strlen( $name ) > 5, new IncorrectValuesException( 'Document should have a title more then five characters.' ) );
+      $this->name = $name;
+      self::$db   = Database::connect();
+    }
+    
+    /**
+     * Retrieve field's value from table
+     *
+     * @param $field
+     *
+     * @return mixed
+     */
+    public function getValue( $field ) {
+      try {
+        $result = self::$db->query( 'SELECT ' . mysqli_escape_string( $field ) . ' from document WHERE name="' . mysqli_escape_string( $this->name ) . '" LIMIT 1' );
+        
+        return $result;
+      } catch (Exception $ex) {
+        echo "There is an error with retrieving result. Please, try alter again.";
+        
+        return FALSE;
+      }
+    }
+    
+  }
+  
+  /**
+   * Helper to work with documents list
+   *
+   * Class DocumentsRepository
+   */
+  class DocumentsRepository {
+    protected static $docs = [];
+    
+    public function addDocument( $doc ) {
+      self::$docs[] = $doc;
+    }
+    
+    public function removeDocument( $name, $r_index = NULL ) {
+      if ( count( self::$docs ) > 0 ) {
+        $removed_index = NULL;
+        if ( ! is_null( $r_index ) ) {
+          $removed_index = $r_index;
+        } else {
+          for ( $index = 0; $index > count( self::$docs ); $index ++ ) {
+            if ( strtolower( trim( $name ) ) == strtolower( trim( self::$docs[ $index ] ) ) ) {
+              $removed_index = $index;
+              break;
+            }
+          }
+        }
+        if ( ! is_null( $removed_index ) ) {
+          array_splice( self::$docs, $removed_index, 1 );
         }
-        return $list;
+      }
+    }
+  }
+  
+  /**
+   *
+   * Class User
+   */
+  class User {
+    
+    protected $docs;
+    
+    public function __construct(DocumentsRepository $docs) {
+      $this->docs = new DocumentsRepository();
+    }
+    
+    /**
+     * Assign new document to user
+     *
+     * @param $name
+     */
+    public function makeNewDocument( $name ) {
+      $doc = new Document($name, $this);
+      $this->docs->addDocument($doc);
+    }
+    
+    /**
+     * Retrieve user's documents
+     *
+     * @return \DocumentsRepository
+     */
+    public function getMyDocuments() {
+      return $this->docs;
+    }
+    
+  }
+  
+  class IncorrectValuesException extends Exception {
+    public function __construct( $message = "", $code = 0, \Exception $previous = NULL ) {
+      parent::__construct( $message, $code, $previous );
+    }
+    
+    public function __toString() {
+      parent::__toString();
     }
-
-}
+  }