Centre for Investigative Journalism in London has made handbooks, which give an insight into investigative journalism and research tools.
‘Story-based Inquiry – A Manual for investigate journalism‘ helps you step-by-step to come from an idea to an actual product. You can download it for free here.
Peter Harms Larsen has made an introduction to investigative journalism, which you can read here.(On danish)
The Norwegian book ‘Gravende journalistikk – metode, prosess og etikk‘ (2012) by Guri Hjeltnes and Morten Møller Warmedal, gives you a thoroughly insight in research methods and tools. (On norwegian)
The Swedish book ‘Gräva och granska: tips och inspiration för journalister‘ (2014) by Britt-Marie Citron and Peder Carlquist, shows how you contradict lobbyism and powerful agencies, and thereby conserve the critic journalism. Read about it here. (On Swedish)
The Swedish journalist Nils Hanson has written the book ‘Grävande journalistik’ (2009). You can read more about it here. (On Swedish)
Christopher Hird is a board member of “The Bureau of Investigative Journalism” and has written a report about, how you get influence in journalism.
The Danish/German journalist Brigitte Alfter has written the book ‘Cross-Border Collaborative Journalism -A Step-By-Step Guide’. It is about how cross-border journalists research together, share knowledge and adapt its publications to their target group. You can read more here.