The United States is negotiating with North Korea to release a joint document when their leaders meet for a historic summit in Singapore on June 12, U.S. government sources said Wednesday.The focus of the talks between U.S. President Donald Trump and North Korean leader Kim Jong Un will be to what extent of "complete denuclearization" Kim will agree. But reaching a deal on the issue will not be easy, leaving uncertainty on whether a joint document will be released.In remarks apparently trying to lower expectations for the outcome of the summit, Trump said last week that he believes Kim is c…READ FULL ARTICLE