Sombultawee, K., and Warit Rinthong. “Purchase Intention Towards Omni-Channel Retail: Buy Online Pickup in Store”. University of the Thai Chamber of Commerce Journal Humanities and Social Sciences, vol. 41, no. 1, Mar. 2021, pp. 89-104, https://so06.tci-thaijo.org/index.php/utccjournalhs/article/view/242774.