- The Mystic Heart. http://www.kashi.org/wp-content/themes/kashi/docs/The%20Mystic%20Heart.pdf. p. 36. [Says that Panikkar was friends with Heidegger, and was instrumental in awakening Heidegger's interest in mysticism!]
- Coelho, Ivo. “Panikkar’s Approach to Reality: Epistemological Foundations.” Raimon Panikkar: Being Beyond Borders. Ed. Johnson J. Puthenpurackal. Bangalore: ATC Publications, 2012. 108-130.
- Puthenpurackal, Johnson J., ed. Raimon Panikkar: Being Beyond Borders. Bangalore: ATC Publications, 2012.