Complex sentence: Anders Jacobsson (born 1963) and Sören Olsson (born 1964) are two Swedish-born cousins who are children's literature and young-adult fiction writers, best known for their books about Sune and Bert.
Split into simpler sentences: Anders Jacobsson (born 1963) and Sören Olsson (born 1964) are two Swedish-born cousins who are writers of children's literature and young-adult fiction. They are best known for their books about Sune and Bert.