Jan Wittenberg was a Dutch painter who was born in 1886. Many works by the artist have been sold at auction, including 'A still life with white rhodondendrons in a small blue vase' sold at Christie's Amsterdam 'Twentieth Century Art' in 2000 for $18,502. The artist died in 1963. (https://www.mutualart.com/Artist/Jan-Wittenberg/64F32A5EDB05EA89#more) Christie's site gives sale price as $24,938 (http://www.christies.com/LotFinder/print_sale.aspx?saleid=10704)