federico ardila
matemático
associate professor . san francisco state university
profesor adjunto . universidad de los andes . colombia
Born in 1993,
published by the name of "F. Ardila, A generalization of Euler's R>=2r,
Crux Math. 21 (1995) p.1-2",
this note is not available electronically elsewhere and it contains
some hard-to-find references.
(I have never even seen one of them; back then I just cited something that
someone cited somewhere.)
So I retyped it and made it self-contained a couple of years later.
That is what this is.