“…Whereas RS is divided into three main state-of-the-art categories such as CBF, CF, and hybrid mode. The CBF comprises of some algorithms named term frequency-inverse domain frequency ( Majid et al., 2013 ; Jiang et al, 2016 ; Wen et al, 2017 ; Psyllidis, Yang & Bozzon, 2018 ) topic modeling ( Wang et al., 2014 ; Lwowski, Rad & Choo, 2018 ), latent Dirichlet allocation ( Wang et al., 2014 ; Fang et al., 2014 ; Pyo & Kim, 2014 ; Jiang et al., 2015 ; Xu, Chen & Chen, 2015 ; Shi et al, 2017 ; Sang, Yan & Xu, 2018 ; Cui et al, 2018 ; Psyllidis, Yang & Bozzon, 2018 ; Nguyen & Cho, 2020 ; Ge et al, 2020 ) feature extraction ( Yu et al, 2016 ), word2vec ( Zhao et al, 2018 ), and natural language processing ( Psyllidis, Yang & Bozzon, 2018 ). On the other hand, CF uses user-item matrix ( Pyo & Kim, 2014 ; Jiang et al., 2015 ; Moro, Rita & Vala, 2016 ; Iqbal et al, 2019 ; Manca, Boratto & Carta, 2018 ; Zhang et al, 2019 ; Ju, Wang & Xu, 2019 ; Margaris, Vassilakis & Spiliotopoulos, 2020 ; Shahbaznezhad, Dolan & Rashidirad, 2021 ), friend-matching graph ( Wang et al., 2014 ), social network analysis ( Wu et al, 2015 ; Wu et al, 2019 ), matrix factorization ( Zhao, Qian & Xie, 2016 ; Yu et al, 2016 ; Zhao et al, 2018 ; Xu, 2018 ), classification ( Yang & Jiang, 2018 ), and graph theory ( Alduaiji, Datta & Li, 2018 ; Ahmadian et al, 2020 ).…”