Table 5.

Hybrid VRS approaches classified by applied algorithms.

Type	References
Matrix factorization	Cui et al., 2014; Roy and Guntuku, 2016; Kvifte et al., 2021; Wang et al., 2021
Deep neural networks	Wang et al., 2015; Gao et al., 2017; Wei et al., 2017; Liu et al., 2019a; Chen et al., 2021
Multi-task learning	Ma et al., 2019; Zhao et al., 2019; Tang et al., 2020; Zhuo et al., 2021; Song et al., 2023
Further approaches	Öztürk and Kesim Cicekli, 2011; Vizine Pereira and Hruschka, 2015; Abbas et al., 2017; Liu et al., 2019b; Kim et al., 2021