public function getColumn( $column )
	{
		if( $column < 0 || $column >= $this->getColumnNumber() )
			throw new OutOfRangeException( 'Column key "'.$column.'" is not valid.' );
		$values = array();
		for( $row = 0; $row < $this->getRowNumber(); $row++ )
			$values[] = $this->getValue( $row, $column );
		return new Alg_Math_Algebra_Vector( $values );
	}