Barry, N. P. (1989). An introduction to modern political theory. Macmillan.
Lua i Stíl Chicago (17ú heag.)Barry, Norman P. An Introduction to Modern Political Theory. Houndmills, Basingstoke, Hampshire: Macmillan, 1989.
Lua MLA (9ú heag.)Barry, Norman P. An Introduction to Modern Political Theory. Macmillan, 1989.
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