Lalita Nilasinwong และ Kantaphon Kuhapatanakul. (2020) Sums of reciprocal triangular numbers. <i>Progress in Applied Science and Technology</i>, <i>10</i>(2), 14-17.Lalita Nilasinwong และ Kantaphon Kuhapatanakul. "Sums of reciprocal triangular numbers". Progress in Applied Science and Technology 10 (2020):14-17.Lalita Nilasinwong และ Kantaphon Kuhapatanakul. Sums of reciprocal triangular numbers. Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi:ม.ป.ท. 2020.