Alkhyat, Salwa H., et al. “Airborne Bacterial Pollution in Clinical Environment, Sana’a - Yemen”. Journal of Advancement in Environmental Solution and Resource Recovery, vol. 2, no. 1, Aug. 2022, pp. 32-37, https://publisher.uthm.edu.my/ojs/index.php/jaesrr/article/view/11222.