Shamelessly copied n pasted but if you're still undecided perhaps this might help ;)
People who think we should remain in:
• Governor of the Bank of England
• International Monetary Fund
• Institute for Fiscal Studies
• Confederation of British Industry
• Leaders/heads of state of every single other member of the EU
• President of the United States of America
• Eight former US Treasury Secretaries
• President of China
• Prime Minister of India
• Prime Minister of Canada
• Prime Minister of Australia
• Prime Minister of Japan
• Prime Minister of New Zealand
• The chief executives of most of the top 100 companies in the UK including Marks and Spencer, BT, Asda, Vodafone, Virgin, IBM, BMW etc.
• Kofi Annan, the former Secretary General of the United Nations
• All living former Prime Ministers of the UK (from both parties)
• Virtually all reputable and recognised economists
• The Prime Minister of the UK
• The leader of the Labour Party
• The Leader of the Liberal Democrats
• The Leader of the Green Party
• The Leader of the Scottish National Party
• The leader of Plaid Cymru
• Leader of Sinn Fein
• Martin Lewis, that money saving dude off the telly
• The Secretary General of the TUC
• Unison
• National Union of Students
• National Union of Farmers
• Stephen Hawking
• Chief Executive of the NHS
• 300 of the most prominent international historians
• Director of Europol
• David Anderson QC, Independent Reviewer of Terrorism Legislation
• Former Directors of GCHQ
• Secretary General of Nato
• Church of England
• Church in Scotland
• Church in Wales
• Friends of the Earth
• Greenpeace
• Director General of the World Trade Organisation
• WWF
• World Bank
• OECD
People who think we should leave:
• Leader of UKIP
• BNP
• Britain First
• Donald Trump
• Keith Chegwin
• David Icke