U.S. Treasury Secretary Janet Yellen and People's Bank of China Governor Pan Gongsheng on Friday held a "substantive and productive" meeting that covered debt, financial architecture and future economic communications, a Treasury spokesperson said. "During the substantive and productive meeting, Secretary Yellen and Governor Pan exchanged views on macroeconomic and financial developments," the spokesperson said in an emailed statement after the meeting on the sidelines of International Monetary Fund and World Bank meetings in Morocco.