Adapted from Tumasjan et al. (2010), table 4 and Jungherr, Jürgens, and Schoen (2012), table 2.
Tumasjan et al. (2010) vu Tumasjan et al. (2010) , Dësch 4 an Jungherr, Jürgens, and Schoen (2012) , Dësch 2.