The ornament of the middle way : a study of the Madhyamaka thought of Śāntarakṣita : including translations of Śāntarakṣita's Madhyamakālamkāra (The ornament of the middle way) and Gyel-tsab's dbU ma rgyan gyi brjed byang (Remembering 'The ornament of the middle way') / by James Blumenthal