There can be no successful global currency system if the financial instruments that are used are denominated in only one currency. Today this is the case and the currency is the dollar.
Medvedev at the Shanghai Cooperative Organization

…possibly placing part of reserves in the financial instruments of partner countries…In the long term, it is beneficial for all and all agree that the world needs a few strong currencies. It cannot happen quickly.
—Arkady Dvorkovich, top economic advisor to Russian President Dmitry Medvedev