Ryland, Robert Shane, “The making of the Government of India Act, 1919”. Ph.D. thesis, Duke University, 1969. Brief summary.

“This study traces the circumstances leading to the enactment of the Government of India Act, 1919, which through substantial electoral reform gave Indian ministers and legislators control over a portion of administration for the first time in the history of British rule.  It also enlarged the Viceroy's Executive Council to which more Indians soon came to be appointed, and established dyarchy in the provinces.” The abstract.