Ahmad. (2014) Monitoring Air Quality by Statistical Control Charts. <i>Journal of SCIENCE and TECHNOLOGY Mahasarakham University</i>, <i>33</i>(2), 157-159.Ahmad. "Monitoring Air Quality by Statistical Control Charts". Journal of SCIENCE and TECHNOLOGY Mahasarakham University 33 (2014):157-159.Ahmad. Monitoring Air Quality by Statistical Control Charts. Mahasarakham University:ม.ป.ท. 2014.