Phil,  A good read - to get you started - is Donald Kagan's Pericles of Athens and the Birth of Democracy (1991). I would particularly recommend Terry Buckley's Aspects of Greek History 750-323 BC - A source-based approach (Routledge 1996) Excellent resource for the 5th century in general. Integrates essential narrative, analysis and selected ancient sources, esp. Thucydides, Aristotle and Plutarch.  Chapters 13 and 18 focus on Pericles' career and his democratic reforms - other chapters have useful information as well. A useful student resource is Gary Kenworthy's chapter on Pericles in the text Personalities from the Past, - (ed. J. Lawless). Gives you a range of relevant ancient and modern sources -and some key issues. All of these texts have bibliographies. A very useful internet resource -for all the ancient sources you need - is Paul Halsall's (Fordham University, New York) Internet Ancient History Source Book which can be found at http://www.forhdam.edu/halsall/ancient/asbook07.html.  Happy reading!