diff --git "a/include/class-wm\\Wikidata.php" "b/include/class-wm\\Wikidata.php"
index 71800cf..42ccaa3 100644
--- "a/include/class-wm\\Wikidata.php"
+++ "b/include/class-wm\\Wikidata.php"
@@ -1,72 +1,78 @@
 <?php
-# Boz-MW - Another MediaWiki API handler in PHP
-# Copyright (C) 2017, 2018 Valerio Bozzolan
+# boz-mw - Another MediaWiki API handler in PHP
+# Copyright (C) 2017, 2018, 2019, 2020, 2021 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/>.
 
 # Wikimedia
 namespace wm;
 
 /**
  * Wikidata singleton instance
  *
  * @see https://www.wikidata.org/
  */
 class Wikidata extends \mw\StaticWikibaseSite {
 
 	/**
 	 * @override
 	 */
 	const UID = 'wikidatawiki';
 
 	/**
 	 * @override
 	 */
 	const API_URL = 'https://www.wikidata.org/w/api.php';
 
 	/**
 	 * Execute a SPARQL query
 	 *
 	 * @param $query string SPARQL query
 	 * @return array
 	 */
 	public static function querySPARQL( $query ) {
+
+		// do some cleanage
+		$query = trim( $query );
+
 		$request = new \network\HTTPRequest( 'https://query.wikidata.org/sparql' );
 		$response = $request->fetch( [
 			'format' => 'json',
-			'query'  => $query
+			'query'  => $query,
 		] );
+
+		// TODO: nice exceptions
 		$response_obj = json_decode( $response );
 		return $response_obj->results->bindings;
 	}
 
 	/**
 	 * Retrieve the label (in English) of a property (from the cache)
 	 *
 	 * @param $property string Property title e.g. P123
 	 * @return string|false Label in English or false
 	 */
 	public static function propertyLabel( $property ) {
 		static $cache;
 		$path = __DIR__ . '/../cache/Wikidata/properties.json';
 		if( ! $cache && file_exists( $path ) ) {
 			$cache = json_decode( file_get_contents( $path ) );
 		}
 		if( isset( $cache->{ $property } ) ) {
 			return $cache->{ $property };
 		}
 		return false;
 	}
 
 }