English: Scan via Heritage Auctions Lot #53394. Cropped from the original image.

English: Photographer and designer unknown. Distributed by Warner Bros.

English: No permission is required because the poster was published prior to 1978 without a copyright notice. While many original copies of this poster included a valid copyright notice ("Copyright ©1976 Warner Bros., Inc."), a significant number did not. A substantial number of total copies distributed in 1976 omitted a notice entirely, possibly due to a printing company's error. As of this upload, Heritage Auctions has past auction listings for 14 posters with a notice, and 13 without:

• With a notice: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
• Without a notice: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13

While a slight majority had notices, the number of posters listed without a notice is large enough to show that the omission was genuine—i.e., not a result of subsequent manipulations or convenient cropping—and widespread enough to remain in circulation four decades after the film's release. US copyright law became more forgiving of omission between 1978 and 1989; new exceptions to copyright waiver during that time included, for example, cases when "notice was omitted from no more than a relatively small number of copies ... distributed to the public" (see "Omission of Notice and Errors of Notice", pp. 2–3). However, such exceptions to waiver did not exist for works published prior to 1978. At that time, copyright forfeiture could not be avoided even if an omission of notice occurred on a "relatively small" number of copies.