private static String getCitedBy(Element e) {
		Elements fl = e.getElementsByClass(THSIS_CITIEDBY_CLASS);
		String text = fl.select("a[href]").first().text();
		// 查找文本中包含的数字
		Pattern pattern = Pattern.compile("\\d+");
		Matcher matcher = pattern.matcher(text);
		String citedBy = "0";
		while (matcher.find()) {
			citedBy = matcher.group(0);
			break;
		}
		return citedBy;
	}