Brahma sutras, 555 aphorisms. The foundation is the upanishas themselves and then a they are called shuti prastana. Shuti means veda - literally what has been heard. So how do you respond to multiple points of view which are ranged against vedanta? E replied to in the brahma sutras plus some additional points about what is the result of all of this. What are the practices to be done? That's brahma s Sutras, 555 Aphorisms.