Oxford University Press released a new research tool this year called Oxford Bibliographies. Each entry (there will be thousands of entries in dozens of academic subjects) consists of an annotated bibliography, broken down into multiple areas of focus  within that topic. Most entries contain a mix of classic and contemporary readings on a subject, so that researchers can understand both the history and the contemporary debate on the topic, and get both depth and breadth. Entries will be updated yearly.

I did the entry on libertarianism, which you can preview here: http://www.oxfordbibliographies.com/view/document/obo-9780199756223/obo-9780199756223-0166.xml?rskey=ammsQP&result=1&q=libertarianism#firstMatch

The TOC:

• General Overviews
• Roots in Early Classical Liberalism
• Contemporary Classical Liberalism
• Libertarianism
• Left-Libertarianism
• Capitalism and Socialism
• Property Rights
• The Welfare State, Social Insurance, and Redistribution
• Government Failure
• Democracy and Citizenship
• Anarchism and Government Authority
• War and International Justice
• Civil Rights
• Environmental Issues
• Critiques of Libertarianism

You may need to log in through your university library. Your university probably already has a subscription or will acquire one soon. I don’t know if there’s any way for unaffiliated people to access this for free.