Some 100 works from the siblings Doris and Thomas Ammann will be sold in May, along with their Warhol silkscreen of Marilyn Monroe, estimated at $200 million.Some 100 works from the siblings Doris and Thomas Ammann will be sold in May, along with their Warhol silkscreen of Marilyn Monroe, estimated at $200 million.Read MoreChristie’s, Ammann, Thomas and Doris, Foundation Zurich, Auctions, Sotheby’s, Phillips Auctioneers LLC, Warhol, Andy, Ryman, Robert, Clemente, Francesco, Twombly, Cy, Porter, Marc (1960- ), Rotter, Alex
