Dobyns, Jay and Johnson-Shelton, Nils and Rometsch, Martin. Falscher Engel: Mein Höllentrip als Undercover-Agent bei den Hells Angels. Ullstein Taschenbuch, Year 2011.

Montaner, Miquel and López, Beatriz and de la Rosa, Josep Lluís. A Taxonomy of Recommender Agents on the Internet. In Artificial Intelligence Review, (19) 4: 285--330, Kluwer Academic Publishers, Year 2003.

Yu, Bin and Singh, Munindar P.. Searching social networks. Proceedings of the second international joint conference on Autonomous agents and multiagent systems. 65--72, ACM, New York, NY, USA, Year 2003.

Parent, S. and Mobasher, B. and Lytinen, S.. An Adaptive Agent for Web Exploration Based of Concept Hierarchies. Proceedings of the 9th International
Conference on Human Computer Interaction. New Orleans, LA, Year 2001.

Steels, L.. The Origins of Ontologies and Communication Conventions in Multi-Agent Systems. In Autonomous Agents and Multi-Agent Systems, (1) 2: 169-194, Year 1998.