“…Since then, a number of other research teams have attempted to estimate intraregional and interregional trade, (c.f. Celik, 2004; Jackson, Schwarm, & Okuyama, 2006; Jackson, Schwarm, Okuyama, & Islam, 2006; Lindall, Olson, & Alward, 2006; Robinson & Liu, 2006; Llano, Esteban, Pérez, & Pulido, 2010; Jackson & Schwarm, 2011; Chun, Kim, & Kim, 2012; Hwang et al, 2016; LeSage & Llano, 2016; Sun, 2018; Zhang, Cheng, & Jin, 2019).…”