วัฒนากุล เ., and บุญธีรารักษ์ พ. “From Needs Analysis to Curriculum Design: The Implementation of a Self- Study ESP Curriculum to Enhance Communicative English Ability of Ticket Sellers of Public Bus Service”. PAYAP UNIVERSITY JOURNAL, vol. 27, no. 2, Jan. 2018, pp. 133-50, doi:10.14456/pyuj.2017.16.