%0 Journal Article
%A V. K. Gavrilov
%T From equality of Pythagoras to equality of Ptolemy
%J Matematičeskoe obrazovanie
%D 2021
%P 2-4
%V 97
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MO_2021_97_1_a0/
%G ru
%F MO_2021_97_1_a0