1. Allum F (2017) The invisible camorra: Neapolitan crime families across Europe. Cornell University Press, New York
2. Ansyley C (2000) The Colombia Encyclopaedia. Colombia University Press, New York
3. Banfield E (1958) The moral basis of a backward society. Free Press, New York
4. Barnes C (2014) Inside the UVF: money, murders and mayhem - the loyalist gang's secrets unveiled. Belfast Telegraph, 13 October
5. Barnes C (2016) Thomas ‘slab’ Murphy takes a £10million hit: busted Armagh plants linked to IRA leader’s gang. The Belfast Telegraph, 29 February