Ключевые слова: background, blank, book, books, collection, color, cover, data, document, education, expertise, glass, group, hardcover, heap, image, information, investigation, isolated, learning, lens, library, literature, magnifier, magnifying, nobody, objects, open, order, page, pages, paper, reading, red, research, row, school, stack, text, textbook, university, variation, view, white, wisdom,