Notes on verification

Core biographical facts (1938 emigration) are well corroborated, but the specific dating of when 'Mayflower' was begun and abandoned in 1945 derives from a single scholar's (Leon Ratermann) archival research at the DNB, not independently cross-verified by a second source. [cascade flags: wikipedia_dropped_other_sources_exist | tier=bronze indep_score=0.525 clusters=2 claim_tier=notable | framework convergence=single on Ratermann's archival research on the Leo Perutz Nachlass at the Deutsche Nationalbibliothek's Deutsches Exilarchiv (upstreams: Deutsches Exilarchiv 1933–1945 der Deutschen Nationalbibliothek (Nachlass Leo Perutz), Leon Ratermann's critical edition 'Der unbekannte Leo Perutz' (Peter Lang, 2022)) — publishers independent, evidence may not be | kind=empirical eligibility=medium (extractor: empirical/high)]