On sale and publication date from the publication date reported to the U.S. Copyright Office found in the Public Catalog, Copyright Catalog (1978 to present) online (http://cocatalog.loc.gov/cgi-bin/Pwebrecon.cgi?DB=local&PAGE=First) retrieved 05 October 2015. Registration date: May 5, 1980. Copyright registration number: TX0000476527. Copyright Claimant:Chicago Tribune/New York News Syndicate.