Hammer, P. E. (1999). The polarisation of Elizabethan politics: The political career of Robert Devereux, 2nd Earl of Essex, 1585-1597. Cambridge University Press.
Lua i Stíl Chicago (17ú heag.)Hammer, Paul E.J. The Polarisation of Elizabethan Politics: The Political Career of Robert Devereux, 2nd Earl of Essex, 1585-1597. Cambridge, [Eng.]: Cambridge University Press, 1999.
Lua MLA (9ú heag.)Hammer, Paul E.J. The Polarisation of Elizabethan Politics: The Political Career of Robert Devereux, 2nd Earl of Essex, 1585-1597. Cambridge University Press, 1999.
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