Stanford Encyclopedia of Philosophy
https://plato.stanford.edu/entries/habermas/
This website contains a summary of Habermas's works and ideas.
"A Lion in the Winter"
https://www.thenation.com/article/a-lion-in-winter/
This article contains a summary of Habermas's works within the context of contemporary politics.
Counterpublics
https://counterpublics.wikispaces.com/Michael+Warner
This webpage provides a brief introduction to a related concept of the public sphere, the "counterpublic."
Media Studies
https://www.media-studies.ca/articles/habermas.htm
This webpage explores Habermas's idea of the public sphere within the context of media studies.
