Siberian Mathematical Journal
Siberian Mathematical Journal > 2019 > 60 > 5 > 896-901
Siberian Mathematical Journal > 2019 > 60 > 5 > 842-845
Siberian Mathematical Journal > 2019 > 60 > 5 > 828-841
Siberian Mathematical Journal > 2019 > 60 > 5 > 886-895