Study Year of
publication 		Selection
(maximum 4 stars) 		Comparability
(maximum 2 stars) 		Outcome
(maximum 3 stars) 		Total score/quality
Schwarz et al. [19] 2018 ★ ★ ★ ★ ★ ★ ★ ★ ★ 9 stars/high quality
Li et al. [32] 2018 ★ ★ ★ ★ ★ ★ ★ ★ 8 stars/high quality
Kim et al. [34] 2014 ★ ★ ★ ★ ★ ★ ★ ★ 8 stars/high quality
Korsch and Peichl [35] 2021 ★ ★ ★ ★ ★ ★ ★ ★ 8 stars/high quality
Xiao et al. [36] 2019 ★ ★ ★ ★ ★ ★ ★ ★ ★ 9 stars/high quality