1. 1. R. M. Bond et al., “A 61-million-person experiment in social influence and political mobilization,” Nature, vol. 489, pp. 295–298, Sep. 2012.
   2. G. Adomavicius and A. Tuzhilin, “Toward consecutive generation of recommender systems: A survey of the progressive and doable extensions,” IEEE Trans. Knowl. Data Eng., vol. 17, no. 6, pp. 734–749, Jun. 2005.
   3. X. Su and T. M. Khoshgoftaar, “A survey of cooperative filtering techniques,” Adv. Artif. Intell., vol. 2009, Aug. 2009, Art. no. 421425, doi: 10.1155/2009/421425.