diff --git "a/include/class-web\\MediaWikis.php" "b/include/class-web\\MediaWikis.php"
index 3556193..03d0d66 100644
--- "a/include/class-web\\MediaWikis.php"
+++ "b/include/class-web\\MediaWikis.php"
@@ -1,67 +1,83 @@
 <?php
 # Boz-MW - Another MediaWiki API handler in PHP
 # Copyright (C) 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/>.
 
 # websites in the Internet
 namespace web;
 
 /**
  * All the MediaWiki instances in the Internet :^)
  */
 abstract class MediaWikis {
 
 	/**
 	 * Get all the registered MediaWiki classes
 	 *
 	 * @return array
 	 */
 	protected static function allClasses() {
 		return [
 			\wm\WikipediaIt      ::class,
 			\wm\Wikidata         ::class,
 			\wm\Commons          ::class,
 			\wm\MetaWiki         ::class,
 			\web\LandscapeforWiki::class,
 		];
 	}
 
 	/**
 	 * Get all the registered MediaWiki instances
 	 *
 	 * @generator
 	 */
 	public static function all() {
 		foreach( self::allClasses() as $classname ) {
 			yield $classname::instance();
 		}
 	}
 
 	/**
 	 * Get a specific MediaWiki instance from its UID
 	 *
 	 * @param $uid string
 	 * @return mw\StaticSite|false
 	 */
 	public static function findFromUID( $uid ) {
 		foreach( self::all() as $one ) {
 			if( $one::UID === $uid ) {
 				return $one;
 			}
 		}
 		return false;
 	}
 
+	/**
+	 * Get all the registered MediaWiki UIDs ordered alphabetically
+	 *
+	 * @return array
+	 */
+	public static function allUIDs() {
+		$all = [];
+
+		foreach( self::all() as $wiki ) {
+			$all[] = $wiki::UID;
+		}
+
+		sort( $all );
+
+		return $all;
+	}
 }
diff --git a/tools/mega-export.php b/tools/mega-export.php
index 5e2436a..ddd76cf 100755
--- a/tools/mega-export.php
+++ b/tools/mega-export.php
@@ -1,201 +1,197 @@
 #!/usr/bin/php
 <?php
 # boz-mw - Another MediaWiki API framework
 # Copyright (C) 2019, 2020 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/>.
 
 // exit if not CLI
 $argv or exit( 1 );
 
 // load boz-mw
 require __DIR__ . '/../autoload.php';
 
 // the number '500' gives to much <This result was truncated because it would otherwise be larger than the limit of 12,582,912 bytes>
 $DEFAULT_LIMIT = 100;
 
 // load configuration
 include 'config.php';
 
 use \cli\Log;
 use \cli\Input;
 use \cli\Opts;
 use \cli\Param;
 use \cli\ParamFlag;
 use \cli\ParamFlagLong;
 use \cli\ParamValued;
 use \cli\ParamValuedLong;
 use \web\MediaWikis;
 use \mw\API\PageMatcher;
 
 // all the available wiki UIDs
-$mediawiki_uids = [];
-foreach( MediaWikis::all() as $site ) {
-	$mediawiki_uids[] = $site::UID;
-}
-$mediawiki_uids = implode( ', ', $mediawiki_uids );
+$mediawiki_uids = implode( ', ', MediaWikis::allUIDs() );
 
 // register all CLI parameters
 $opts = new Opts( [
 	new ParamValuedLong( 'wiki',          "Available wikis: $mediawiki_uids" ),
 	new ParamValuedLong( 'limit',         "Number of revisions for each request" ),
 	new ParamValuedLong( 'file',          "Output filename" ),
 	new ParamFlag(       'help',    'h',  "Show this help and quit" ),
 ] );
 
 $messages = [];
 
 // choosen wiki
 $wiki_uid = $opts->getArg( 'wiki' );
 if( !$wiki_uid ) {
 	$messages[] = "Please specify --wiki=WIKI";
 }
 
 // page titles
 $page_titles = Opts::unnamedArguments();
 if( !$page_titles ) {
 	$messages[] = "Please specify some page titles";
 }
 
 // output filename
 $filename = $opts->getArg( 'file' );
 if( !$filename ) {
 	$messages[] = "Please specify a filename";
 }
 
 $limit = (int) $opts->getArg( 'limit', $DEFAULT_LIMIT );
 
 // show the help
 $show_help = $opts->getArg( 'help' );
 if( $show_help ) {
 	$messages = [];
 } else {
 	$show_help = $messages;
 }
 
 if( $show_help ) {
 	echo "Usage:\n {$argv[ 0 ]} --wiki=WIKI --file=out.xml [OPTIONS] Page_title\n";
 	echo "Allowed OPTIONS:\n";
 
 	$opts->printParams();
 
 	foreach( $messages as $msg ) {
 		echo "\nError: $msg";
 	}
 	echo "\n";
 	exit( $opts->getArg( 'help' ) ? 0 : 1 );
 }
 
 // try to open the file
 $file = fopen( $filename, 'w' );
 if( !$file ) {
 	Log::error( "Can't open file '$filename'" );
 	exit( 1 );
 }
 
 $wiki = MediaWikis::findFromUID( $wiki_uid );
 $wiki->login();
 
 $requests = $wiki->createQuery( [
 	'action' => 'query',
 	'titles' => $page_titles,
 	'prop'   => 'revisions',
 	'rvprop' => [
 		'ids',
 		'flags',
 		'timestamp',
 		'user',
 		'userid',
 		'size',
 		'slotsize',
 		'sha1',
 		'comment',
 		'content',
 	],
 	'rvslots' => 'main',
 	'rvlimit' => $limit,
 ] );
 
 // total number of revisions
 $total = 0;
 
 // do not print to the out
 $out  = '<mediawiki xmlns="http://www.mediawiki.org/xml/export-0.10/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mediawiki.org/xml/export-0.10/ http://www.mediawiki.org/xml/export-0.10.xsd" version="0.10" xml:lang="it">' . "\n";
 foreach( $requests as $request ) {
 
 	foreach( $request->query->pages as $page ) {
 
 		if( isset( $page->missing ) ) {
 			Log::error( "Page '{$page->title}' is missing" );
 			exit( 1 );
 		}
 
 		$alert_much_revisions = true;
 		foreach( $page->revisions as $i => $revision ) {
 
 			// avoid nonsense revisions
 			if( empty( $revision->comment ) ) {
 				if( $alert_much_revisions ) {
 					$count = count( $page->revisions );
 					if( $count !== $limit ) {
 						Log::warn( "response with $count revisions instead of $limit: consider to lower your limit" );
 						$alert_much_revisions = false;
 					}
 				}
 				continue;
 			}
 
 			$total++;
 
 			foreach( $revision->slots as $slot ) {
 
 				// avoid nonsense slots
 				if( empty( $slot->contentmodel ) ) {
 					continue;
 				}
 
 				$safe_user    = htmlentities( $revision->user      );
 				$safe_userid  = htmlentities( $revision->userid    );
 				$safe_comment = htmlentities( $revision->comment   );
 				$safe_model   = htmlentities( $slot->contentmodel  );
 				$safe_format  = htmlentities( $slot->contentformat );
 				$safe_text    = htmlentities( $slot->{'*'}         );
 
 				$out .= "<revision>\n";
 					$out .= "\t<id>{$revision->revid}</id>\n";
 					$out .= "\t<parentid>{$revision->parentid}</parentid>\n";
 					$out .= "\t<timestamp>{$revision->timestamp}</timestamp>\n";
 					$out .= "\t<contributor>\n";
 						$out .= "\t\t<username>$safe_user</username>\n";
 						$out .= "\t\t<id>$safe_userid</id>\n";
 					$out .= "\t</contributor>\n";
 					$out .= "\t<comment>$safe_comment ?></comment>";
 					$out .= "\t<model>$safe_model</model>\n";
 					$out .= "\t<format>$safe_format</format>\n";
 					$out .= "\t<text xml:space=\"preserve\" bytes=\"{$slot->size}\">$safe_text</text>\n";
 					$out .= "\t<sha1>{$revision->sha1}</sha1>\n";
 				$out .= "</revision>\n";
 			}
 		}
 	}
 
 	// write the file in chunks
 	fwrite( $file, $out );
 	$out = '';
 }
 
 Log::info( "you mega-exported $total revisions! nice shot!" );
 
 fwrite( $file, "</mediawiki>\n" );
 fclose( $file );