This work is in the public domain because it was published in the United States between 1978 and March 1, 1989 without a copyright notice, and its copyright was not subsequently registered with the U.S. Copyright Office within 5 years. Unless its author has been dead for several years, it is copyrighted in the countries or areas that do not apply the rule of the shorter term for US works, such as Canada (70 pma), Mainland China (50 pma, not Hong Kong or Macau), Germany (70 pma), Mexico (100 pma), Switzerland (70 pma), and other countries with individual treaties. See this page for further explanation. Deutsch ∙ English ∙ español ∙ français ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ português ∙ português do Brasil ∙ русский ∙ sicilianu ∙ slovenščina ∙ 中文（简体） ∙ 中文（繁體） ∙ +/−

This advertisement did not have a copyright notice and is in the public domain.

From the US Copyright Office Circular 3. Page 3, Contributions to Collective Works. (A magazine is a "collective work.")

A notice for the collective work will not serve as the notice for advertisements inserted on behalf of persons other than the copyright owner of the collective work. These advertisements should each bear a separate notice in the name of the copyright owner of the advertisement.

Furthermore Tandy Corporation failed to register appropriately within 5 years as required by law.