1. Aoki, S., & Uchida, O. (2011). A method for automatically generating the emotional vectors of emoticons using weblog articles. WSEAS, Venice, Italy,132-136
2. Ball, M. (2022). The metaverse: and how it will revolutionize everything. New york: Liveright Publishing
3. Research-paper recommender systems: a literature survey
4. Borchert, D. M. (2006). The Encyclopedia of Philosophy, 2nd ed. Detroit, MI, USA: Thomson Gale, 22-35
5. Predicting the Present with Google Trends