TY  - JOUR
AU  - V. K. Gavrilov
TI  - From equality of Pythagoras to equality of Ptolemy
JO  - Matematičeskoe obrazovanie
PY  - 2021
SP  - 2
EP  - 4
IS  - 1
UR  - http://geodesic.mathdoc.fr/item/MO_2021_1_a0/
LA  - ru
ID  - MO_2021_1_a0
ER  -