title: Letter: Limitations of methotrexate and citrovorum-factor treatment.
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000009:adverse effects*; D002648:Child; D004359:Drug Therapy, Combination; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D008727:Methotrexate / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D012516:Osteosarcoma / Q000188:drug therapy
chemical_list: D000970:Antineoplastic Agents; D002955:Leucovorin; D008727:Methotrexate