Kodcharin, P., Youngchuay, U. and Chinwetkitvanich, S. 2018. Natural Radioactivity in Groundwater in Phra Nakhon Si Ayutthaya Province. Applied Environmental Research. 40, 3 (Aug. 2018), 11–18. DOI:https://doi.org/10.35762/AER.2018.40.3.2.