Work of breathing during nasal continuous positive airway pressure in preterm infants: a comparison of bubble vs variable-flow devices.
Liptsen E, Aghai ZH, Pyon KH, Saslow JG, Nakhla T, Long J, Steele AM, Habib RH, Courtney SE. Work of breathing during nasal continuous positive airway pressure in preterm infants: a comparison of bubble vs variable-flow devices. J Perinatol. 2005 Jul; 25(7):453-8.