[1] Univ Autonoma Nuevo Leon, Monterrey, Mexico
[2] Hosp Gen Mexico Dr Eduardo Liceaga, Mexico City, DF, Mexico
[3] Univ Autonoma Nuevo Leon, Pediat, Monterrey, Mexico
[4] Hosp Infantil Mexico Dr Federico Gomez, Mexico City, DF, Mexico
[5] Inst Segurodad Social Estado Mexico & Municipios, Toluca, Mexico
[6] Hosp Especialidades Chihuahua, Chihuahua, Mexico