sentences: "Baum's productivity slackened somewhat after the 1906-7 peak, with four books in 1908, and three each in 1909 and 1910, but five in 1911 and four in 1912; and then two or three books a year for the remainder of his life.Baum had already been friendly with Britton and Reilly before he signed with them; their friendships continued and developed over the ensuing years.