Bhatia S, Landier W, Hageman L, Chen Y, Kim H, Sun CL, Kornegay N, Evans WE, Angiolillo AL, Bostrom B, Casillas J, Lew G, Maloney KW, Mascarenhas L, Ritchey AK, Termuhlen AM, Carroll WL, Wong FL, Relling MV. Systemic Exposure to Thiopurines and Risk of Relapse in Children With Acute Lymphoblastic Leukemia: A Children's Oncology Group Study. JAMA Oncol. 2015 Jun; 1(3):287-95.