letter
- https://www.dead.net/archives/1971/clippings/warner-brothers-letter-promo-pictures
- https://www.dead.net/archives/1971/clippings/warner-brothers-letter-promo-display
- https://www.dead.net/archives/1971/clippings/warner-brothers-advertising-letter
- https://www.dead.net/archives/1971/clippings/warner-bros-advertising-letter-page-2
- https://www.dead.net/archives/1972/clippings/letter-europe-72-1-2
- https://www.dead.net/archives/1972/clippings/letter-europe-72-2-2
