Èngel'son Ya L

Publications in Math-Net.Ru

1. On the square root of a linear operator in locally convex spaces
   
   Dokl. Akad. Nauk SSSR, 122:5 (1958),  755–758
2. A conditional extreme of functionals in linear topological spaces
   
   Mat. Sb. (N.S.), 45(87):4 (1958),  417–422