[1] Childrens Natl Hlth Syst, Div Hosp Med, Washington, DC USA
[2] George Washington Univ, Sch Med, Washington, DC USA
[3] Univ Rochester, Med Ctr, Dept Pediat, Rochester, NY 14642 USA
[4] Childrens Hosp Montefiore, Bronx, NY USA
[5] Amer Acad Pediat, Elk Grove Village, IL USA
[6] Monroe Carell Jr Childrens Hosp Vanderbilt, Dept Pediat, Nashville, TN USA
[7] Vanderbilt Univ, Sch Med, Nashville, TN 37212 USA
[8] Dartmouth Inst Hlth Policy & Clin Effectiveness, Lebanon, NH USA
[9] Childrens Hosp Dartmouth, Dept Pediat, Geisel Sch Med, Lebanon, NH USA