"As this court previously observed, the market place is the appropriate place to resolve authentication disputes"
In another significant recent ruling, the First Department affirmed the dismissal of a failure-to-authenticate claim against the Warhol Foundation. The (short) decision is here. Background here (with an accurate prediction from Josh Baer). You can keep winning these suits, but you can't stop people from bringing them. Which is one reason the Warhol Foundation (and others) have gotten out of the authentication business altogether.