According to Wikipedia: «The Bhagavad Gita … is a 700-verse Hindu scripture that is part of the ancient Sanskrit epic Mahabharata… The Sānatsujātiya refers to a portion of the Mahābhārata, a Hindu epic. It appears in the Udyoga Parva (book), and is composed of five chapters… The Anugita is part of the Asvamedhikaparva a book of the Sanskrit epic Mahabharata. It contains Krishna's conversation with Arjuna when Krishna decided to return to Dwaraka after restoring to the Pandavas, their kingdom. The main topics discussed are transmigration of souls, means of attaining liberation, description of gunas and ashramas, dharma, and the effects of tapas or austerity.»
