On a theorem of D. Ryabogin and V. Yaskin about detecting symmetry
  We give a simple deduction of a recent theorem of D. Ryabogin and V. Yaskin, about detecting symmetry of star bodies in ${\Bbb{R}}^n$ with $C^1$ radial functions --- via their conical section functions --- from an older theorem of us. 
E. Makai, Jr., H. Martini, T. \'Odor
math.CA