Marcus Floyd Book and Joseph Truman Book

I am looking for ancestors of Marcus Floyd Book (?-1908) and his brother Joseph Truman Book (1869-1953) from either S.E. Arkansas or possibly N.E. Missouri. I have an old family tree that I downloaded in the mid '90s from a long lost site that leads me to believe that they were the sons of Michael Book (1839-1900) and Nancy Harvill (?-1893). They may have had two other brothers: John Quincy Book (1863-1951) and William Henry Book (1866-?). This tree may not be accurate because itseems to be rather incomplete. Can anyone verify any of this information? Marcus Floyd's first wife was Minnie Richards (?-?) and they had two children. His second wife was Olive Ellen Coonce (1882-1965) and they also had two children. Joseph Truman's first wife was Elizabeth McCormick(?-1907) and they had six children. His second wife was also Olive Ellen Coonce and they had eight children. Olive Ellen Book is my maternal grandmother and my mother is Cresa Adalee Nordan (1924-2009), Grandma's second youngest child. If anyone can provide additional information and /or correct any mistakes I have made ( especially Marcus and Joseph's ancestors), I would greatly appreciate it.