Critical Discourse Analysis (CDA), recently phrased as Critical Discourse Studies (CDS) is analytically robust and applicable in many fields to explore interdisciplinary and complex sociopolitical issues. I think works by Wodak and Meyer and their Discourse Historical Approach (DHA) of CDS will be relevant to your work on national identity issues, particularly on how identity is expressed in text and re/produced in everyday language use in the media and political discourses. Ruth Wodak and colleagues have studies discourses of nation and national identity in Australia, and identity politics and the media in the European Union. You might want to take a look at (1) Wodak, de Cillia, Reisigl, & Liebhart. (2009) The Discursive Construction of National Identity, Edinburgh: Edinburgh University Press. (2) Wodak & Richardson. (eds) (2013) Analyzing Fascist Discourse: European Fascism in Talk and Text, London: Routledge. (3) Wodak, R. (2010). “Communicating Europe”: Analyzing, interpreting, and understanding multilingualism and the discursive construction of transnational identities, and other recent publications and references cited therein on the topic. Good luck.

There are many publications in this field. A simple literature search should provide you with many publications relating to your research area. Other than what has been mentioned, you can also check, among others, Richardson, J. (2006), Analysing Newspapers: An Approach from Critical Discourse Analysis; Talbot, M. (2007), Media Discourse: Representation and Interaction: Kalyango, Y. & Kopytowska, M.W. (2014), Why Discourse Matters: Negotiating Identity in the Mediatized World.

Why Discourse Matters. Negotiating Identity in the Mediatized World. Edited By Yusuf Kalyango, Jr. and Monika Weronika Kopytowska. Peter Lang 2014.

Discourse Studies, Vol. 3, No. 4, November 2001. SPECIAL ISSUE: Authenticity in media discourse.