00558naa#a2200181#i#450# EN\INFRA-M\bibl\2137 20260315134912.7 2308-4898 20140303b2014####ek#y0engy0150####ca RUS RU Status and Trends of Geometrical-Graphic Training as a Component of Engineering Education in Bulgaria Journal article Moscow INFRA-M Academic Publishing LLC. 2014 7 с. Journal article local Popov M. Leparov M. Nikolaevich zh-szf.ru