1. Marsh, S.: Formalising Trust as a Computational Concept. PhD thesis, University of Stirling, Department of Computer Science and Mathematics (1994)
2. McKnight, D., Chervany, N.: The Meanings of Trust. MISRC 96-04, University of Minnesota, Management Informations Systems Research Center, University of Minnesota (1996)
3. Gray, E., O’Connell, P., Jensen, C., Weber, S., Seigneur, J.M., Yong, C.: Towards a Framework for Assessing Trust-Based Admission Control in Collaborative Ad Hoc Applications. Technical Report 66, Department of Computer Science, Trinity College Dublin (2002)
4. Matthews, R.: Six Degrees of Separation. World Link (2000)
5. Milgram, S.: The Small World Problem. Psychology Today 61 (1967)