Narasimhaswami, B. V., Life of Sai Baba (4 vols, Mylapore, Chennai: All India Sai Samaj, 1955-6; first edn composite volume, 2002). For the chapter on Upasni Baba, see p. 1, http://www.saiamrithadhara.com/mahabhakthas/upasani_baba.html, see also Godamasuta, ed., The Life Sketch and Quintessence of the Talks of Sadguru Upasani Baba Maharaja (Sakori: Shri Sati Devitai Upasani Maharaj, n.d.), pp. 5-7.
Harper, Marvin Henry, Gurus, Swamis, and Avataras: Spiritual Masters and Their American Disciples (Philadelphia: Westminster Press, 1972) p. 39, see also, Narasimhaswami, B. V., Life of Sai Baba (4 vols, Mylapore, Chennai: All India Sai Samaj, 1955-6; first edn composite volume, 2002). For the chapter on Upasni Baba, see pp.1-2, http://www.saiamrithadhara.com/mahabhakthas/upasani_baba.html
