Secondary sanctions against Chinese institutions : assessing their utility for constraining North Korea : hearing before the Subcommittee on National Security and International Trade and Finance of the Committee on Banking, Housing, and Urban Affairs, United States Senate, One Hundred Fifteenth Congress, first session, on examining how Chinese banks, businesses, and persons provide North Korea with direct and indirect access to financial markets and resources, allowing Pyongyang to evade or mitigate international sanctions, May 10, 2017.