00512naa#a2200181#i#450# EN\INFRA-M\bibl\278 /en/manage/index 20250529034718.4 2308-4898 20130603b2013####ek#y0engy0150####ca RUS RU «Impossible» geometrical figures Journal article Moscow INFRA-M Academic Publishing LLC. 2013 2 с. Journal article local Stepura Ekaterina fht.editorum.ru /en/manage/index