The American century : art and culture 1950 - 2000 ; [published on the occasion of the Exhibition "The American Century: Art & Culture 1900 - 2000" at the Whitney Museum of American Art. Part I, 1900 - 1950, April 23 to August 22, 1999, and Part II, 1950 - 2000, September 26, 1999, to February 13, 2000]