R. Khamthung, N. Suwonnaroop, N. Kitnarong, and N. Watthayu, “The Relationships among Knowledge of Glaucoma, Perceived Susceptibility, Received Information and Preventive Behavior of Glaucoma in Population at Risk”, ์Nurs Sci J Thail, vol. 29, no. 2, pp. 93–101, Jun. 2011.