import { Book } from './book';
import { Bookshelf } from './bookshelf';
export declare class BaseBookshelf implements Bookshelf {
    private _books;
    constructor(books: Book[]);
    readBooks(): Book[];
    readingBooks(): Book[];
    readBooksGroupedByYear(): {
        [key: number]: Book[];
    };
    private readBookYears;
    private sortRecentlyFinishedBooksFirst;
    private sortRecentlyStartedBooksFirst;
}