Can't help you about Dede, at the moment.  But Carter Pann wrote at least
one other work besides a piano concerto (which I took to be a misprint, at
first, for Carter's piano concerto- bad Eric!)- Barcelona Portraits, I
think- available in a library in Ohio...

-Eric Schissel

 [I can find reference to a female composer by the name of Dede Duson.  Her
 works appear to be mainly choral in nature, and she is probably still with
 us.  -Dave]