sentences:  Eckart contributed to the posthumous publication of some works by the mathematician John von Neumann.Eckart married Edith Louise née Frazee in 1926; they were divorced in 1948.In 1958, he married Klara Dan von Neumann, the widow of the mathematician John von Neumann; Klara died in 1963 in a drowning accident, officially ruled a suicide.