Nekotorye voprosy teorii grupp / red. kollegii︠a︡ E. M. Levich, B. I. Plotkin, otv. red. A. I. TokarenkoB. I. Plotkin, Latvia) Rizhskiĭ algebraicheskiĭ seminar (1969 Rīga · First published 1971Open the Tome
