Zhou JY, Shi R, Yu HL, Zeng Y, Zheng WL, Ma WL. Association between polymorphic sites in thymidylate synthase gene and risk of non-Hodgkin lymphoma: a systematic review and pooled analysis. Leuk Lymphoma. 2012 Oct;53(10):1953–60. doi: 10.3109/10428194.2012.673226. PMID: 22397721.