The book of hymns, inspired by the vision of the Upanishads is titled Atma Bodha, 'self knowledge'. Shankaracharya devoted his short, powerful life to one subject alone: knowledge of and identification with the source of consciousness, the source of all life, known as Brahman.
Bhagavad Gita by Neema Majmudar
Gita Study Group - Swami Tyagananda
Part 2 - Learn Sanskrit
Mundakopanishat by MLN Murthy
Foundations of Vedantic Practice with Bede Clifford