Columbia subject headings:
Authors, Russian--20th century--Biography.
Authors, Russian--20th century--Correspondence.
Zadonskiĭ, Nikolaĭ--Correspondence.
Zadonskiĭ, Nikolaĭ.
Harvard subject headings:
Authors, Russian--20th century--Biography
Authors, Russian--20th century--Correspondence
Zadonskiĭ, Nikolaĭ
Zadonskiĭ, Nikolaĭ--Biography.
Zadonskiĭ, Nikolaĭ--Correspondence.
Princeton subject headings:
Authors, Russian--20th century--Biography.
Authors, Russian--20th century--Correspondence.
Zadonskiĭ, Nikolaĭ--Biography.
Zadonskiĭ, Nikolaĭ--Correspondence.