Hellwig, Martin F. 1949- Hellwig, Martin Hellwig, M. F. (Martin F.) Hellwig, Martin Friedrich 26194 2026-03-10 13:10:30 2026-03-06 15:26:10 naf viaf repec wikidata author https://fraser.stlouisfed.org/author/martin-f-hellwig-1949 https://fraser.stlouisfed.org/api/author/26194