Somchai Saengsawang และ Bunlur Emaruchi. (2010) Time distance minimization contracting unit for primary care service using geographical information system : case study Nakhonnayok province. Mahidol University:ม.ป.ท.Somchai Saengsawang และ Bunlur Emaruchi. 2010. Time distance minimization contracting unit for primary care service using geographical information system : case study Nakhonnayok province. ม.ป.ท.:Mahidol University;Somchai Saengsawang และ Bunlur Emaruchi. Time distance minimization contracting unit for primary care service using geographical information system : case study Nakhonnayok province. ม.ป.ท.:Mahidol University, 2010. Print.