Ключевые слова: background, book, bookshelf, classics, collection, composition, copy, cover, data, document, education, expertise, group, hardback, hardcover, heap, information, isolated, knowledge, learning, library, literary, literature, object, office, page, paper, pile, reading, research, school, science, simple, space, stack, study, text, textbook, university, vertical, white, wisdom, writing,