A military report on the country of Bhutan, containing all the information of military importance which has been collected up to date (12th July 1866). Lt Charles Metcalfe MacGregor. Calcutta: QMG's Dept, 1873.
Military handbook of general information on India. Lt Frederick Hugh Sykes, rev by Cpt Claude Lumsden Norman & Cpt Charles John Bruce Hay. Simla: Intelligence Branch, 1908.