Unal, Sule, et al. “The Absence of Peripheral Blood Blasts at Diagnosis May Predict CNS Involvement or CNS Relapse in Pediatric Acute Lymphoblastic Leukemia Patients”. The Turkish Journal of Pediatrics, vol. 50, no. 6, Dec. 2008, pp. 537-41, https://turkjpediatr.org/article/view/2486.