T. . Hongthong, S. . Boonmaya, P. A. . Sativaro, P. B. . Suddhiyano, and N. N. Ngambussabongsophin, “Motivation and Practical Guidance of Volunteerism in The Royal Cremation Ceremony of His Majesty King Bhumibol Adulyadej, Rama IX”, JIBS, vol. 10, no. 1, Dec. 2018.