public BookData getByTitle(String word){
		BookData subset = new BookData();
		
		//check each book in books
		for(int i=0; i<books.size(); i++){
			String temp = books.get(i).getTitle();
			temp=temp.trim().toLowerCase();
			word=word.trim().toLowerCase();
			
			//check if the book title contains the given word
			if(temp.contains(word)){
				subset.addBook(books.get(i));
			}
		}
		
		//return any matching books
		return subset;
	}