incorporeal, corporeal source in case of spells and damage

[Franc Crosses]

In the incorporeal description it is said "... Even when hit by spells or magic weapons, it takes only half damage from a corporeal source..."

What is/isn't a corporeal source?

Do for ex. fireball, call lightning, cone of cold, lightning bolt and generally spells with an energy descriptor, half or full damage?

[dragonhunterq]

The caster is the source of spells.
The wielder of the weapon is the source for weapon damage.