static void addBook()
{
Console.Write("Nhap so luong sach can them:");
int n = Int32.Parse(Console.ReadLine());
for (int i = 0; i < n; i++)
{
Book book = new Book();
Console.WriteLine("******Cuon sach thu {0}****", i + 1);
book.inputBook();
if (!ischecked(authorList, book.ButDanh))
{
Console.WriteLine("Đây là 1 bút danh mới");
Author author = new Author(book.ButDanh);
author.inputAuthorWithoutButDanh();
authorList.Add(author);
}
bookList.Add(book);
}
}