“…The nationality of these authors is concentrated in twenty-two countries as shown in table 1. However, the most representative countries are Germany (Dlouhy, et al, 2017), Brazil (Franco and Picchi, 2016), Chile (Salvatierra, et al, 2015;Matta, et al, 2018), United States (Smith and Ngo, 2017;Alves, Azambuja and Arnous, 2016), India (Patel, Karia and Pandit, 2018), England (Tezel, et al, 2016) and Norway (Torp, Knudsen and Ronneberg, 2018). Other authors consulted came from Australia (Shou, et al, 2017), Ecuador (Martínes, Tommelein and Alvear, 2017), Estonia (Leonova, Ballard and Gehbauer, 2017), Finland (Singh, 2018), Ireland (Kemmer, et al, 2016), Lebanon (Hatoum, et al, 2018), Morocco (Hicham, Taoufiq and Aziz, 2016), Mexico (Dlouhy, et al, 2018), New Zealand (Hunt and Gonzalez, 2018), Netherlands (Vrijhoef, Dijkstra and Koutamanis, 2018), Peru (Murguía, Brioso and Pimentel, 2016), Palestine (Enshassi and Abu Zaiter, 2014), South Africa (Monyane, Emuze and Crafford, 2018) and Pakistan (Memon, et al, 2018).…”