Technology of production of gas-oil pipes using method of high-frequency welding at PJSC "Interpipe NMTZ" - Ju. N. Antipov; E. V. Dmitrenko; A. V. Kovalenko; S. A. Gorjanoj; A. A. Rybakov; S. E. Semenov; T. N. Filipchuk (Automatic Welding, 2014)