Harry Harrison
3 appearances across 3 restored issues — every one readable in full, free.
Analog British Edition, Vol. 18 No. 1 — 1962 “Sense of Obligation” (serial) · p.4 Read the full issue (132 pages) → 
Analog British Edition, Vol. 18 No. 2 — 1962 “Sense of Obligation” (serial) Read the full issue (132 pages) → 
Amazing Stories, July 1968 — 1968 “THE FUTURE OF THE FUTURE” (article) · p.4 Read the full issue (148 pages) → Appearances are extracted from each issue's own printed contents page; entries we can't read confidently are withheld rather than guessed.