Some biographical information might be found in the following:
God's Word Among Men: Papers in Honour of Fr Joseph Putz, SJ, Frs J. Bayart, SJ, J. Volckaert, SJ, and P. de Letter, SJ. Ed. G. Gispert-Sauch. Delhi: Vidyajyoti Institute of Religious Studies, 1973.
"Father Joseph Putz, SJ." A Tribute by J. Bayart, SJ. ix-xiv.
"Father Julian Bayart, SJ." A Tribute by J. D'Souza, SJ. xv-xviii.
"Father Jules Volckaert, SJ." A Tribute by M. Dullard, SJ. xix-xxii.
"Father Prudent de Letter, SJ." A Tribute by Archbishop L.T. Picachy, SJ. xxiii-xxvi.
In the same volume see also:
R. Panikkar, "Vac in the Sruti." 3-24.
R. De Smet. "Highlights in the Life of Faith (Sraddha) in India." 39-58.
K. Rahner. "Christ in Non-Christian Religions." 95-104.
S. Grant. "Reflections on the Mystery of Christ suggested by a Study of Sankara's Concept of Relation." 105-16.
J. Dupuis. "The Cosmic Influence of the Holy Spirit and the Gospel Mesage." 117-38.
G. Gispert-Sauch. "Grace and the Christian Call." 167-180.
J. Mattam. "Abbe Jules Monchanin and India, 'The Land of the Trinity'." 195-230.
E. Hambye. "Robert de Nobili and Hinduism." 325-34.