public static function convertToRoman( $integer )
	{
		Deprecation::getInstance()
			->setErrorVersion( '0.8.5' )
			->setExceptionVersion( '0.9' )
			->message( sprintf(
				'Please use %s (%s) instead',
				'public library "CeusMedia/Math"',
			 	'https://packagist.org/packages/ceus-media/math'
			) );
		arsort( self::$roman );
		$roman = "";																		//  initiating roman number
		if( is_numeric( $integer ) && $integer == round( $integer, 0 ) )					//  prove integer by cutting floats
		{
			while( $integer > 0 )
			{
				foreach( self::$roman as $key => $value )									//  all roman number starting with biggest
				{
					if( $integer >= $value )												//  current roman number is in integer
					{
						$roman	.= $key;													//  append roman number
						$integer	-= $value;												//  decrease integer by current value
						break;
					}
				}
			}
			$keys	= array_keys( self::$shorts );
			$values	= array_values( self::$shorts );
			$roman	= str_replace( $keys, $values, $roman );								//  realize shortcuts
			return $roman;
		}
		else
			throw new InvalidArgumentException( "Integer '".$integer."' is invalid." );
	}