[1] Univ Utah, Dept Pediat, Primary Childrens Hosp, Div Pediat Hematol Oncol, Salt Lake City, UT USA
[2] Univ Tennessee, Coll Med, Dept Pediat, Div Pediat Cardiol, Memphis, TN USA
[3] St Jude Childrens Res Hosp, Cardiopulm Serv, 332 N Lauderdale St, Memphis, TN 38105 USA
[4] North Carolina State Univ Lib, Raleigh, NC USA
[5] Univ Utah, Eccles Hlth Sci Lib, Salt Lake City, UT USA
[6] Univ Memphis, Sch Publ Hlth, Div Epidemiol Biostat & Environm Hlth, Memphis, TN USA
[7] St Jude Childrens Res Hosp, Dept Hematol, 332 N Lauderdale St, Memphis, TN 38105 USA