1. An early work, not commented on by Śaṅkara, which explains the hymns addressed to Nārāyana.
2. A late work forming the tenth book of the Taittirīya Āraṇyaka. It celebrates Prājāpati and an extensive pantheon, including Durgā.
"Mahānārāyaṇīya Upaniṣad." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (October 22, 2018). https://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/mahanarayaniya-upanisad
"Mahānārāyaṇīya Upaniṣad." The Concise Oxford Dictionary of World Religions. . Retrieved October 22, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/mahanarayaniya-upanisad