By BBC News, June 7, 2016
Hillary Clinton is looking to tighten her grip on the Democratic presidential nomination, after an AP count said she had already won enough delegates.
Six states are going to the polls, with California (543 delegates) and New Jersey (142) the big prizes.
Associated Press said Mrs Clinton had already reached the 2,383 delegates needed, taking into account pledges of support from so-called superdelegates.
