Copyright 1941 by Comic Magazines, Inc.
The on-sale date is the publication date reported in the U. S. Copyright Office filing.
Writer revision from John Devlin to ? by Craig Delich 2013-4-7. The Who's Who does not indicate a writing credit for Devlin on this strip.
Even though the Who's Who doesn't list Gustavson as a writer of the strip, Mike Kooiman and Jim Amash state in the Quality Companion that he created the strip and wrote it, so the question mark behind the name has been removed by Craig Delich 2013-1-19.