here are some sources.
Message from King Felipe- on official monarchy website address to nation 3.10.2017
Spanish Government news.
Government of catalan has official results
UK House of Commons briefing paper - 31 august has usful background on the issues from a British perspective.
Guardian coverage of the referendum
Guardian news stories.
New York Times
The website www.cataloniavotes.eu is an initiative of the Public Diplomacy Council of Catalonia (DIPLOCAT),' a public-private partnership designed to foster dialogue and connect the citizens of Catalonia with the rest of the world. ' Its website has news, debates , a timeline of events and background it also includes academic discussion papers.
also useful Opinion Studies Center which has recent barometers in (in Catalan, Spanish and English)
LSE EOPP blog
Chatham house papers and briefings 2014 onwards
Amnesty international discussion police response.
CIDOB barcelonia. search the website for papers and reports.
Real instituto Elcano- papers and reports