@Override
  @Transactional
  public List<AuthorEntity> getBookAuthors(int id) throws NoSuchEntityException {
    BookEntity book = bookDao.getNotNull(id);
    List<AuthorEntity> list = Lists.newArrayList();

    if (book.getBookToAuthor() != null) {
      for (BookAuthorEntity b2a : book.getBookToAuthor()) list.add(b2a.getAuthor());
    }

    return list;
  }