The grey market has been a constant source of litigation and appeals in the United States. The same fundamental question arises under patent law and copyright law, namely whether or not a good sold abroad lawfully is still protected by United States intellectual property law for the purposes of resale. When purchased domestically, a copyrighted good may be resold by the purchaser under the first sale doctrine contained at 17 U.S.C. §109(c). Similarly, a patented good may be re-sold under the patent exhaustion doctrine. In 2013, the United States Supreme Court largely discussed the legality of the grey market when it decided Kirtsaeng v. John Wiley & Sons, Inc. where it held that a sale abroad of a copyrighted good triggers the first sale doctrine. The decision is largely understood to apply to patented goods as well.