Most Don Rosa stories have the letters D.U.C.K. hidden somewhere in the first panel.
This is an acronym for Dedicated to Unca Carl from Keno.
Because Disney would not allow for personal signatures in the comics, and thought that D.U.C.K. looked too much like one, Don Rosa has made a habit of hiding the letters in various unlikely places.
This website lists most of Rosa's covers and first pages, and provides a way to display the dedication in most of them.
In some cases, we were unable to find the D.U.C.K. dedication. If you find one that isn't listed on this website, please send an email at firstname.lastname@example.org.