Columbia subject headings:
Authors, Polish--20th century--Biography.
Educators--Poland--Biography.
Korczak, Janusz, 1878-1942.
Harvard subject headings:
Authors, Polish--20th century--Biography.
Educators--Poland--Biography
Korczak, Janusz, 1878-1942
Princeton subject headings:
Educators--Poland--Biography.
Korczak, Janusz, 1878-1942.