Hauser, Peter C., Thusitha W.T. Rupasinghe, and Robin Tan. “A Simple Photometer Based on a New Tri-Colour Light-Emitting Diode”. CHIMIA 49, no. 12 (December 20, 1995): 492. Accessed April 27, 2024. https://www.chimia.ch/chimia/article/view/1995_492.