Argumentation analysis

Hi everyone!

I am a Russian student and this year I graduate from the university. Currently I am preparing my thesis where I am going to analyse argumentation in English.

For my analysis, I would like to use some written texts in English. The texts should contain argumentative dialogues.

Could anybody suggest me such texts (something from modern English literature, for example)? It seems that plays would be better than novels, for they consist of dialogues.

I am thinking about the most appropriate choice, but I have just very few ideas now... I like "The Picture of Dorian Gray" very much for its brilliant dialogues, but I would like to include something more modern (written in 1960s or later) into my analysis.

Thank you!