TABLE 3.

Papers based on used technique/learning approach.

Technique (learning approach)	Related studies
Supervised	Lei et al. (2015), Shen and Kuo (2015), Lubis et al. (2016), Buenaño-Fernández et al. (2017), Estrada et al. (2020), Hew et al. (2020), Kastrati et al. (2020)
Unsupervised	Liu et al. (2017a), Yan et al. (2019)
Lexicon-based	Cobos et al. (2019b), Lundqvist et al. (2020)
Supervised and unsupervised	Moreno-Marcos et al. (2018)
Lexicon-based and supervised	Cobos et al. (2019a), Capuano et al. (2020), Capuano and Caballé. (2020), Dina et al. (2021), Onan. (2021), Qi and Liu. (2021), (Li et al., 2019)
Lexicon-based and unsupervised	Ezen-Can et al. (2015)
Lexicon-based and unsupervised or supervised	Badache and Boughanem (2014)
Statistical analysis	Dowell et al. (2015), Koutsodimou and Jimoyiannis. (2015), Au et al. (2016), Holstein and Cohen (2016), Lee et al. (2016), Liu. (2016), Liu et al. (2017a), Lee et al. (2020)
N/A	Sa’don et al. (2014), Crossley et al. (2015), O’Malley et al. (2015), Crossley et al. (2016), Nissenson and Coburn (2016), Rahimi and Khosravizadeh (2018), Martínez et al. (2019), Zhang et al. (2020)