Hume, R. E., & Haas, G. C. O. (1931). The thirteen principal Upanishads: Translated from the Sanskrit with an outline of the philosophy of the Upanishads and an annotated bibliography (2nd ed. rev.). Oxford University Press.

Hume, Robert Ernest, and George C. O. Haas. The Thirteen Principal Upanishads: Translated from the Sanskrit with an Outline of the Philosophy of the Upanishads and an Annotated Bibliography. 2nd ed. rev. London ; New York: Oxford University Press, 1931.

Hume, Robert Ernest, and George C. O. Haas. The Thirteen Principal Upanishads: Translated from the Sanskrit with an Outline of the Philosophy of the Upanishads and an Annotated Bibliography. 2nd ed. rev. Oxford University Press, 1931.