Immediate source is an eBay action that is/was at [www.ebay.com/itm/1955-Maria-Tallchief-Frederic-Franklin-Ballet-Russe-de-Monte-Carlo-Trade-Ad-/230950410396?pt=LH_DefaultDomain_0&hash=item35c5b7989c] The eBay seller says that it is a faithful scan of a 1955 magazine ad.
Author
Scanned by eBay seller vintageadstudio1. The original ad is from Columbia Artists Management, Inc.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.