Tanwa Arpornthip. (2020) Different schemes for replacing conventional light bulbswith LED bulbs for greatest return on investment. <i>Songklanakarin Journal of Science and Technology</i>, <i>42</i>(2), 329-338.Tanwa Arpornthip. "Different schemes for replacing conventional light bulbswith LED bulbs for greatest return on investment". Songklanakarin Journal of Science and Technology 42 (2020):329-338.Tanwa Arpornthip. Different schemes for replacing conventional light bulbswith LED bulbs for greatest return on investment. Research and Development Office, Prince of Songkla University:ม.ป.ท. 2020.