Columbia subject headings:
Functional analysis.
Kreĭn, M. G. (Mark Grigorʹevich), 1907-1989.
Harvard subject headings:
Functional analysis.
Kreĭn, M. G. (Mark Grigorʹevich), 1907-
Kreĭn, M. G. (Mark Grigorʹevich), 1907-1989.
Princeton subject headings:
Functional analysis.
Kreĭn, M. G. (Mark Grigorʹevich), 1907-1989.