"What are the museums to do, they ask, if the artist retained the copy­right, if the artist cannot be found, or if a group of heirs is arguing about who owns which copyright?"

That's a quote from today's Supreme Court decision in the Kirtsaeng case, holding that the first-sale doctrine applies to works made abroad.  Which (among other things) means museums can continue to display foreign-made works in their collections.  Adam Liptak's New York Times story is here.  Sergio Muñoz Sarmiento comments here.  Yale's Margot Kaminski has a good post here.