sentences:  Nathan Lieberman was actively involved in the operation, serving as general manager of the firm at the time of his death in 1955, at the age of 82.Mortimer Lieberman attended Northwestern University in Evanston, Illinois, then moved to New York City, going to work as an editor for "Amusements Magazine" under Donald Flamm and adopting the pen name Lee Mortimer.Broadway columnist Walter Winchell, in a March 12, 1931 column, called out Mortimer for having reported that Winchell was changing newspapers, reporting that Mortimer, "an up and coming youngster now editing Amusements for Donald Flamm, goes a little gay with facts too, however, when he reports that I am shifting rags."