(Newser) – Sources tells NPR and the AP that Bernie Sanders plans to endorse Hillary Clinton during a campaign stop next Tuesday in New Hampshire. Clinton's campaign has announced the event in New Hampshire but hasn't confirmed Sanders will be there. Despite a multitude of people calling for him to do so, Sanders has resisted endorsing Clinton, attempting to win concessions from the Democratic Party first. Sources say he was finally convinced to endorse Clinton, at least in part, when she agreed to use part of his college tuition plan, specifically making public colleges and universities free to families making less than $125,000 per year. The endorsement may give the Democrats a united front heading into the convention and general election. (Read more Bernie Sanders stories.)