A writer and illustrator for Disney that carried on the tradition of Carl Barks' famous works on Donald Duck, Rosa also assembled complete runs of every comic book published between 1966 and the late '80s, purchasing his books from local newsstands in Louisville, Kentucky. He decided to part with the 1970-present portion of his collection in 1995, sold through Steve Wyatt at San Diego Comic-Con that year. Rosa's remaining collection also contains a large, high grade accumulation of comics from the '50s, purchased complete by Rosa, which possibly represents a "pedigree within a pedigree." His collection has no identifying markings.