Widoroni, Christianus Eko Purwanto, et al. “The Effect of Exercises Pursed Lips Breathing (PLB) Changes To Scale Of Breathlessness and Oxygen Saturation In COPD Patients At Hospital Dr. Soedarso Pontianak ”. Journal Of Nursing Practice, vol. 5, no. 1, Oct. 2021, pp. 176-81, doi:10.30994/jnp.v5i1.169.