उपनिषद्वाक्यकोशः

One of the major difficulties in appreciating the various commentaries on Vedanta Sutras and other ancient Indian philosophical texts is that numerous citations from the Upanishads and the Bhagavadgita are found in them without any exact authenticated reference to the original source. With a view to overcoming this difficulty by providing relevant cross-references, as also to furnishing useful material to students of philology and lexicography, Col. Jacob has compiled this book. This volume owes its existence to a pressing sense of need.