VALUES (
        NULL,
        " . $dbh->quote($hash{$key}{'title'}) . ", 
        " . $dbh->quote($hash{$key}{'authors'}) . ",  
        " . $dbh->quote($hash{$key}{'isbn'}) . ",  
        " . $dbh->quote($hash{$key}{'pages'}) . ",  
        " . $dbh->quote($hash{$key}{'publisher'}) . ",  
        " . $dbh->quote($hash{$key}{'publication_date'}) . ",
        " . $dbh->quote($hash{$key}{'image_small'}) . ",  
        " . $dbh->quote($hash{$key}{'image_medium'}) . ",  
        " . $dbh->quote($hash{$key}{'url_amazon'}) . ",   
        NULL)";