1. Amichai-Hamburger, Y.: Potential and promise of online volunteering. Comput. Human Behav. 24(2), 544–562 (2008)
2. Conti, M., Das, S.K., Bisdikian, C., Kumar, M., Ni, L.M., Passarella, A., Roussos, G., Tröster, G., Tsudik, G., Zambonelli, F.: Looking ahead in pervasive computing: challenges and opportunities in the era of cyber-physical convergence. Pervasive Mob. Comput. 8(1), 2–21 (2012)
3. Grossi, R., Gupta, A., Vitter, J.S.: High-order entropy-compressed text indexes. In: Proceedings of the 14th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pp. 841–850, Philadelphia, PA, USA. Society for Industrial and Applied Mathematics (2003)
4. Howe, J.: Crowdsourcing: A definition. Tracking the Rise of the Amateur, Crowdsourcing (2006)
5. Howe, J.: The rise of crowdsourcing. Wired Mag. 14(6), 1–4 (2006)