00581naa#a2200181#i#450# EN\INFRA-M\bibl\13164 20250205234826.3 2308-4898 20160919b2016####ek#y0engy0150####ca RUS RU The Duality Principle Is the Theoretical Basis of Interrelation of Synthetic and Analytical Methods of Solving Geometric Problems Journal article Moscow INFRA-M Academic Publishing LLC. 2016 7 с. Journal article local Ivanov G. Dmitrieva I. M. zh-szf.ru