Lamthong, Wittaya, Kamon Yodyadthai, and Pisol Senawongse. 2019. “Output Intensity of LED Light Curing Units over a 4-Year Period of Clinical Use”. Mahidol Dental Journal 39 (2). Bangkok, Thailand:153-63. https://he02.tci-thaijo.org/index.php/mdentjournal/article/view/204837.