'America: The Third Century.' Four posters from the portfolio commissioned by the Mobil Oil Corporation, 1976. Roy Lichtenstein (1923-1987) 'Bicentennial Poster;' Christo (b.1935) 'Texas Mastaba;' Ben Schonzeit (b.1935) 'Yankee Flame;' & Robert Rauschenberg (1925-2008) 'Deposit.' 89x61cm (sheet) Estimate $100-200