Aktama, Galih, et al. “The Effect of the Covid-19 Free Operation Path Protocol on the Incidence of Lung Complications in Postoperative Elective Patients at Dr. Moewardi Hospital Surakarta”. Bioscientia Medicina : Journal of Biomedicine and Translational Research, vol. 5, no. 11, June 2021, pp. 1030-6, https://doi.org/10.32539/bsm.v5i11.369.