There is a text/book called wheel of sharp weapons by an ancient teacher named dharmarakshita. Essentially this text explains the inner workings of karma, as in what actions lead to what result.
My gripe with this is that as far as I know the inner workings of karma was not explained by Buddha, in fact that it is one of the four imponderables!
What I am trying to understand is if this text is based on the actual Buddhas teachings or is it again some later distortion or watering down of later Buddhists.
So if anyone has any source of the tipitika of where or what sutra Buddha explained the results of karma I would be appreciated if you could direct me in the right direction.