Riesel numbers appeared in the answer to my question Solving $2^{x+1} m -1=p^y$ for prime $p$ and natural $x,y$. The original reference
Riesel, Hans (1956). "Några stora primtal". Elementa. 39: 258–260
on them appears to be rather hard to find, it's not on AMS' Mathscinet or on ZBMath. R.Guy's book "Unsolved problems in number theory" does not list it in its references to Riesel's work, instead giving a book by Riesel, where I cannot find the relevant data.
Does anyone have access to this short paper in the "Elementa", an education-oriented magazine which stopped publications long time ago? I'd like to be able to check the original paper before citing it.