public void getauthors(int layer,List<String>list)
	{
		if(layer>2)
		{
			return;
		}else{
			for(String id:list){
				if(!totalpaper.contains(id)){
					List<String>tmp=getAuthorList.getAuthors(Integer.parseInt(id));
					for(String au:tmp){
						if(!authors.contains(au))
							authors.add(au);
					}
					List<String>papers=getCitationIDList.getCitationPapers(Integer.parseInt(id));
					totalpaper.add(id);
					if(papers.size()>0){
						getauthors(layer+1,papers);
					}
				}
			}
		}
	}