Robert Silverberg
3 appearances across 3 restored issues — every one readable in full, free.
Authentic Science Fiction Monthly No. 81 — 1957 “Collecting Team” · p.66 Read the full issue (130 pages) → 
Authentic Science Fiction Monthly, No. 82 — 1957 “Songs of Summer” · p.49 Read the full issue (130 pages) → 
Amazing Stories, July 1969 — 1969 “UP THE LINE” (serial) · p.76 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.