
https://judiciary.house.gov/uploadedfiles/house_trial_brief_final.pdf?et_rid=804757741&s_campaign=truthcons:newsletter

http://library.fes.de/pdf-files/bueros/athen/13572.pdf

https://scholar.princeton.edu/sites/default/files/mgilens/files/gilens_and_page_2014_-testing_theories_of_american_politics.doc.pdf