Sequelize join and limit

I am trying to form a query with Sequelize to join and select + limit. Let me illustrate the problem:

I have a Many-to-Many relationship: Book - Reader. A reader can have many books and a book can have many readers.

Given the id of a Book, I would like to page through all of its Readers. Here's what I currently have tried, it has some issues. First the paging does not work. Second it still selects all the attributes of Book as well as Reader, when I only need Reader (I'm throwing away all of Book).

/**
 * Get all Readers of a Book.
 *
 * @param {Number} bookId id of the book
 * @param {Number} limit number of readers to retrieve
 * @param {Number} offset number of readers to skip 
 * @return {Promise} contains an array of readers
 */
function getBookReaders(bookId, limit, offset) {
  return Book.findOne({
    id: bookId,
    include: [Reader],
    limit: 10,
    offset: 30
  }).then(function(book) {
    return book.readers;
  });
}

Any suggestions on how to form this query correctly?