This industry group comprises establishments primarily engaged in publishing newspapers, magazines, other periodicals, books, directories and mailing lists, and other works, such as calendars, greeting cards, and maps. These works are characterized by the intellectual creativity required in their development and are usually protected by copyright. Publishers distribute or arrange for the distribution of these works. Publishing establishments may create the works in-house, contract for, purchase, or compile works that were originally created by others. These works may be published in one or more formats, such as print and/or electronic form, including proprietary electronic networks. Establishments in this industry may print, reproduce, or offer direct access to the works themselves or may arrange with others to carry out such functions. Establishments that both print and publish may fill excess capacity with commercial or job printing. However, the publishing activity is still considered to be the primary activity of these establishments.