Ven. Indapala, C. Chantimachaiamorn, and P. V. Thitavangso, “The Development of English-Speaking Skill by Using Problem-Based Learning for the First Year B.A. Students of Teaching English (International Program) in Education Faculty at Mahachulalongkomrajavidyalaya University”, Mahachulalongkornrajavidyalaya University, vol. 5, no. 3, pp. 37–49, Dec. 2024.