**Chapter 3**

external sources. *Journal of Statistical Mechanics: Theory and Experiment*, 2020

*Theory of Complexity - Definitions, Models, and Applications*

[34] Janusz Holyst, Krzysztof Kacperski, and Frank Schweitzer. Social impact models of opinion dynamics. *Annual Reviews of Computational Physics*, 9:253–

[35] Krzysztof Kacperski and Janusz Holyst. Opinion formation model with strong leader and external impact: a mean field approach. *Physica A:*

*Statistical Mechanics and its Applications*,

(1):013402, 2020.

269(2):511–526, 1999.

273, 2002.

**40**
