Meesang, W., and N. Navakakam. “TYPE AND QUANTITY OF BACTERIA IN AIR FROM THE MAIN SERVICE ACTIVITIES IN THE OFFICE, CASE STUDY: FACULTY OF SCIENCE’S OFFICE UDON THANI RAJAHAT UNIVERSITY, SAM PHRAO CAMPUS”. Research Journal Phranakhon Rajabhat : Science and Technology, vol. 17, no. 1, June 2022, pp. 1-9, https://li01.tci-thaijo.org/index.php/PRRJ_Scitech/article/view/251447.