Narasak Muangkaew และ Somchai Pathomsiri. (2011) A GIS-Based approach for the determination of service level agreement (SLA) on the transportation network : a case study of gas stations in Bangkok metropolitan region. Mahidol University:ม.ป.ท.Narasak Muangkaew และ Somchai Pathomsiri. 2011. A GIS-Based approach for the determination of service level agreement (SLA) on the transportation network : a case study of gas stations in Bangkok metropolitan region. ม.ป.ท.:Mahidol University;Narasak Muangkaew และ Somchai Pathomsiri. A GIS-Based approach for the determination of service level agreement (SLA) on the transportation network : a case study of gas stations in Bangkok metropolitan region. ม.ป.ท.:Mahidol University, 2011. Print.