Romano, S., Salvaggio, A., Hirata, R. P., Lo Bue, A., Picciolo, S., Oliveira, L. V. F. de, & Insalaco, G. (2011). Upper airway collapsibility evaluated by a negative expiratory pressure test in severe obstructive sleep apnea . Clinics, 66(4), 567-572. https://doi.org/10.1590/S1807-59322011000400008