Full article here.
http://fas.org/blogs/security/2015/05/china-mirv/
Pentagons Chinese military power 2015 report here.
http://www.defense.gov/pubs/2015_China_Military_Power_Report.pdf
DF-31 warhead is estimated to weight roughly 450 kg's so DF-5B should be able to haul at least four of them.