Columbia subject headings:
Gumilev, N. (Nikolaĭ), 1886-1921--Congresses.
Gumilev, N. (Nikolaĭ), 1886-1921--Criticism and interpretation.
Harvard subject headings:
Gumilev, N. (Nikolaĭ), 1886-1921--Congresses.
Gumilev, N. (Nikolaĭ), 1886-1921--Criticism and interpretation--Congresses.
Gumilev, N. (Nikolaĭ), 1886-1921--Criticism and interpretation.
Princeton subject headings:
Gumilev, N. (Nikolaĭ), 1886-1921--Congresses.
Gumilev, N. (Nikolaĭ), 1886-1921--Criticism and interpretation.