00528naa#a2200181#i#450# EN\INFRA-M\bibl\24584 20241219094008.4 2308-4898 20181225b2018####ek#y0engy0150####ca RUS RU General Principles for Formation of Ruled Surfaces. Part 1 Journal article Moscow INFRA-M Academic Publishing LLC. 2018 11 с. Journal article local Математика. 51 RUS Sal'kov N. A. naukaru.ru