Can a cat get pregnant....?

A female cats litter usually contains kittens from numerous fathers (or at least numerous 'batches' of sperm) . This I know. But, Can the female store the sperm indefinately? More to the point, can a female cat get pregnant after having a litter without having copulated after the litter? (Can she store the sperm left over from the first litter and 'spontaneously' get preganant?)