Borg U.; Eriksson I.; Lyttkens L.; Sjöstrand U.; Wattwil M. A Preliminary Report on Experimental Studies of Continuous Positive-pressure Ventilation (CPPV) and High-frequency Positive-pressure Ventilation (HFPPV). Upsala Journal of Medical Sciences, v. 84, n. 2, p. 109-117, 1 Jun. 1979.