(a) Every editor or proprietor of a book, newspaper or serial publication and every manager of a partnership or incorporated association by which a book, newspaper or serial publication is issued, is chargeable with the publication of any matter contained in such book, newspaper or serial publication. But in every prosecution for libel the defendant may show in his defense that the matter complained of was published without his knowledge or fault and against his wishes, by another who had no authority from him to make the publication and whose act was disavowed by him as soon as known.
(b) The author of a libel in all cases is equally guilty and shall be punished in the same manner as the publisher, owner, or proprietor of the newspaper or other printed publication in which the libelous article appears.