The following are references of some of the non traditional research done on the Gita. By no means can this list be considered exhaustive.
THE SOCIAL ROLE OF THE GITA: HOW AND WHY, was published in Delhi by Urmila Agarwal in 1993. The book is available from Motilal Banarsidass.
UPANISHADS, GITA, AND BIBLE : A COMPARATIVE STUDY OF HINDU AND CHRISTIAN SCRIPTURES written by Parrinder, Edward Geoffrey. London : Sheldon Press, 1975.
THE GITA & THE QURAN : A COMPARATIVE STUDY : AN APPROACH TO NATIONAL INTEGRATION Mohammad Khan Durrany. 1st ed. Durrany, Mohammad Khan, 1934- Delhi : Nag Publishers, 1982.
THE GITA AS IT WAS : REDISCOVERING THE ORIGINAL BHAGAVADGITA Sinha, Phulgenda, 1924- La Salle, Ill. : Open Court, 1987, c1986
THE GITA IN THE LIGHT OF MODERN SCIENCE [BY] R. B. Lal. Foreword by R. R. Diwakar. Bombay, Somaiya Publications [1970]
THE GITA IN WORLD LITERATURE edited by C.D. Verma. New Delhi : Sterling Publishers, c1990.
THE TRICOLOR GITA, Gita as a text written by three individuals.