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Marshall, T. H. (1949/1965). Citizenship and Social Class. Class, Citizenship, and Social Development. Essays by T.H. Marshall. T. Bottomore. New York, Anchor Books: 71-134.
Mau, S. (2022). Sorting Machines: The Reinvention of the Border in the 21st Century. London, Polity Press.
Shachar, A. (2020). The Shifting Border. Legal cartographies of migration and mobility. Ayelet Shachar in Dialogue. Manchester, Manchester University Press.
Soysal, Y. (1994). Limits of Citizenship. Migrants and Postnational Membership in Europe. Chicago, University of Chicago Press.
 One tantalising aspect of this book, published well before the start of the war in Ukraine, is that it draws attention in several places to the low-level warfare in Ukraine’s eastern regions since 2014, as if the author sensed what was coming. He probably did, because on pp. 374-80 the book offers a very interesting discussion of how the Russian state has, since the early 1990s, instrumentalised citizenship rules for ethnic Russians in neighbouring countries for a policy of expansion and destablisation that has come to the boil in the war over Ukraine’s independence and territorial integrity.
 See, for example, ‘Citizenship Struggles: 25th Anniversary Special Issue’, edited by Leah Bassel and Engin Isin, Citizenship Studies 26: 4-5 (2022), 361-725.