There are 2 ways to get the dwarf one. One is to talk to the only dwarf in the Dwarven Bread Inn. Refuse his gift and he will leave, and leave the scroll on the table ( it is always there but he gets kind of mad if you take it. ):D
The other way is to wait and do a quest for the Dwarven King. He will give you a scroll, too.
The Imp scroll is in the Imp's castle, in the Dark Forest.