Inhaled nitric oxide usage in preterm infants in the NICHD neonatal research network: Inter-site variation and propensity evaluation

W. E. Truog, L. D. Nelin, A. Das, D. E. Kendrick, E. F. Bell, W. A. Carlo, R. D. Higgins, A. R. Laptook, P. J. Sanchez, S. Shankaran, B. J. Stoll, K. P. Van Meurs, M. C. Walsh