public String toString(){
		
		String keyIndent = "";
		int max_key_digits = 6;
		for(int i=0; i< max_key_digits-(""+id).length(); i++ ) keyIndent = keyIndent + " ";
		
		String pageIndent = "";
		int max_page_digits = 5;
		for(int i=0; i< max_page_digits-(""+page).length(); i++ ) pageIndent = pageIndent + " ";
		
		return "" + id + keyIndent + bookcode + "   " + page + pageIndent + title;
	}