Madubun, S. E. P., O. W. Angkejaya, B. J. Que, F. de Lima, and C. R. Titaley. “EtCO2 Levels in Medical Students Wearing N95 Masks”. Jurnal Respirasi, vol. 9, no. 3, Sept. 2023, pp. 169-75, doi:10.20473/jr.v9-I.3.2023.169-175.