Allison, David G.; Lambert, Peter A. (2015). "Modes of Action of Antibacterial Agents:: Dihydrofolate Reductase Inhibitors". Molecular Medical Microbiology. pp.583–598. doi:10.1016/B978-0-12-397169-2.00032-9.
Morgan SL, Baggott JE, Lee JY, Alarcon GS (1998). "Folic acid supplementation prevents deficient blood folate levels and hyperhomocysteinemia during long-term, low-dose methotrexate therapy for rheumatoid arthritis: Implications for cardiovascular disease prevention". Journal of Rheumatology. 25 (3): 441–6. PMID9517760.