public function addArticle( $name, $volume )
	{
		if( !$this->hasVolumeLeft( $volume ) )
			throw new OutOfRangeException( 'Article "'.$name.'" does not fit in this Packet "'.$this->name.'".' );
		if( !isset( $this->articles[$name] ) )
			$this->articles[$name]	= 0;
		$this->articles[$name]++;
		$this->volume	+= $volume;
	}