Notes on verification

Well-corroborated by NCI, NIH/PMC, and Science History Institute sources. Nitrogen mustard (1942-43) and aminopterin (1947-48) are consistently cited as the first chemotherapy agents producing measurable clinical remissions, marking the historical start of the chemotherapy era, though 'effective' is interpreted loosely as inducing temporary remission rather than cure. [tier=gold indep_score=0.983 clusters=3 claim_tier=notable | framework convergence=partial on Standard oncology history narrative tracing origin of chemotherapy to WWII-era nitrogen mustard and Farber's antifolate work (upstreams: National Cancer Institute historical timeline, Yale nitrogen mustard trials (Goodman & Gilman, 1943), Sidney Farber's aminopterin trials (1947-48)) — publishers independent, evidence may not be | kind=empirical eligibility=medium]