Metcalf, Barbara D. Islamic Revival in British India: Deoband, 1860-1900. Princeton University Press,2014,p.207–. ISBN 978-1-4008-5610-7.««The basis of that shift was the decision made by the government in 1837 to replace Persian as court language by the various vernaculars of the country. Urdu was identified as the regional vernacular in Bihar, Oudh, the North-Western Provinces, and Punjab, and hence was made the language of government across upper India.» (La base d'aquest canvi va ser la decisió presa pel govern el 1837 de substituir el persa com a llengua de cort per les diverses llengües vernacles del país. L'urdú es va identificar com la llengua vernacular regional a Bihar, Oudh, les províncies del nord-oest i el Panjab i, per tant, es va convertir en la llengua de govern a l'alta Índia.»
Ahmad, Rizwan«Scripting a new identity: The battle for Devanagari in nineteenth-century India».Journal of Pragmatics,40,7,1 juliol 2008,p.1163–1183. DOI: 10.1016/j.pragma.2007.06.005.
