public BookData getByPageNum(int min, int max){
		BookData subset = new BookData();
		
		//reorder min and max if necessary
		if(min > max){
			int temp = min;
			min = max;
			max = temp;
		}
		
		//check each book in books
		for(int i=0; i<books.size(); i++){
			int temp = books.get(i).getNumPages();
			//if the book lenght falls in the given range add it to subset
			if(temp >= min && temp <=max){
				subset.addBook(books.get(i));
			}
		}
		//return any matching books
		return subset;
	}