diff --git "a/include/class-wb\\DataValue.php" "b/include/class-wb\\DataValue.php"
index 4465a40..8d03f08 100644
--- "a/include/class-wb\\DataValue.php"
+++ "b/include/class-wb\\DataValue.php"
@@ -1,69 +1,98 @@
 <?php
 # Boz-MW - Another MediaWiki API handler in PHP
-# Copyright (C) 2017, 2018 Valerio Bozzolan
+# Copyright (C) 2017, 2018, 2019 Valerio Bozzolan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 # Wikibase
 namespace wb;
 
 /**
  * A generic DataValue is part of a Snak.
  */
 class DataValue {
 
 	var $type;
 	var $value;
 
 	/**
+	 * Constructor
+	 *
 	 * @param $type  string Type
 	 * @param $value mixed  Value
 	 */
 	public function __construct( $type, $value ) {
 		$this->setType(  $type )
 		     ->setValue( $value );
 	}
 
+	/**
+	 * Get the type
+	 *
+	 * @return string
+	 */
 	public function getType() {
 		return $this->type;
 	}
 
+	/**
+	 * Get the value
+	 *
+	 * @return mixed
+	 */
 	public function getValue() {
 		return $this->value;
 	}
 
+	/**
+	 * Set the type
+	 */
 	public function setType( $type ) {
 		$this->type = $type;
 		return $this;
 	}
 
+	/**
+	 * Set the value
+	 *
+	 * @param  mixed $value
+	 * @return self
+	 */
 	public function setValue( $value ) {
 		$this->value = $value;
 		return $this;
 	}
 
+	/**
+	 * Static constructor from a standard object
+	 *
+	 * @param  object $data
+	 * @return self
+	 */
 	public static function createFromData( $data ) {
 		if( ! isset( $data['type'], $data['value'] ) ) {
 			throw new WrongDataException( __CLASS__ );
 		}
 		return new self( $data['type'], $data['value'] );
 	}
 
 	/**
+	 * Get this object in form of a string
+	 *
 	 * @return string
 	 */
 	public function __toString() {
-		return $this->getValue();
+		return json_encode( $this->getValue() );
 	}
 }