Phansi, Piyawan, Jantira Koin, and Duangjai Nacapricha. 2020. “Determination of Phosphate in Surface Water of Lopburi Province Using a Simple Flow Injection Analytical System”. RMUTP Research Journal 14 (2). Bangkok, Thailand:122-34. https://doi.org/10.14456/jrmutp.2020.26.