Thechawattanapanicharoen, T., and M. Ekkaphan. “The Influence of Reference Group on Consumers Decision to Purchase Big Bikes in Roi Et Province”. Journal of Roi Et Rajabhat University, Vol. 15, no. 1, Apr. 2021, pp. 63-74, https://so03.tci-thaijo.org/index.php/reru/article/view/241776.