Fernandez E, Watterberg KL, Faix RG, Yoder BA, Walsh MC, Lacy CB, Osborne KA, Das A, Kendrick DE, Stoll BJ, Poindexter BB, Laptook AR, Kennedy KA, Schibler K, Bell EF, Van Meurs KP, Frantz ID, Goldberg RN, Shankaran S, Carlo WA, Ehrenkranz RA, S?nchez PJ, Higgins RD. Definitions of cardiovascular insufficiency and relation to outcomes in critically ill newborn infants. Am J Perinatol. 2015 Sep; 32(11):1024-30.