The item has no copyright markings on it as can be seen in the links above. At lower left is the Tooker logo-this is the company who produced the poster. At lower left is "Litho in USA" and a number which is probably the print job number.
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.
{{Information |Description=Poster for the 1937 film''Song of the City''. |Source=[http://www.ebay.com/itm/Song-of-the-City-One-Sheet-Movie-Poster-Margaret-Lindsay-amp-Dean-Jagger-1937-/191285677690?pt=LH_DefaultDomain_0&hash=item2c8983ce7a&nma=true&si=...