Harvard University Art Museums officials have decided to sell a Mary Cassatt painting that Christie's auction house estimates could bring as much as $5 million when it goes on the block Dec. 1. The brightly colored oil, titled ''Mother and Two Children," explores a familiar motif for the American-born artist, who spent most of her life in France. | Breaking News Alerts Painted in 1906, the work was given to Harvard in 1922 by Ernest G. Stillman, a member of the class of 1907. The painting has rarely been on display. Money from the sale will go into the museums'...