Complex sentence: Rowena A. Morrill (born 1944) is an American artist working in science-fiction and fantasy illustration who is credited as one of the first female artists to impact paperback cover illustration.
Split into simpler sentences: Rowena A. Morrill (born 1944) is an American artist, working in science-fiction and fantasy illustration. She is credited as being one of the first women artists to impact paperback cover illustration.