Jofi Joseph is quoted in this Bloomberg article posted yesterday on the challenges of extending the interim agreement on Iran's nuclear program if talks falter on a broader permanent deal:
http://www.bloomberg.com/news/2014-07-03/iran-nuclear-negotiator-visits-un-monitors-to-pave-way-for-plan.html
http://www.bloomberg.com/news/2014-07-03/iran-nuclear-negotiator-visits-un-monitors-to-pave-way-for-plan.html