Over five decades, K\'aroly Tandori has published 49 definitive research
papers in the
Acta Scientiarum Mathematicarum.
In these papers he has solved several hard problems
and considerably expanded the theory of orthogonal series.
His results have been frequently quoted in monographs and
in more than a thousand papers worldwide.
The Medal was presented to Károly Tandori at 14:00, November 8, 2001
in the Bolyai Institute.
On this occasion he delivered a lecture ``On my papers appeared in the Szegedian ACTA".