Yes, they drop from the daily SP quests. Though another good way to farm them if you're dedicated enough, is to just farm a shit-ton of Ultimate demons in UEs, and you'll stock up a whole bunch. In fact if you hardcore farm UE ULTs, you'll have enough to do the daily exchange for the holy stars as well, and basically get a free star every day from 1 UE to the next. It's a nice lil' perk for those who actually contribute in UEs. :>