Columbia subject headings:
Jewish radicals--Poland--Biography.
Jews--Poland--Biography.
Mendel, Hersh, 1893-1968.
Harvard subject headings:
Jewish radicals--Poland--Biography.
Jews--Poland--Biography.
Mendel, Hersh, 1893-1968.
Princeton subject headings:
Jewish radicals--Poland--Biography.
Jews--Poland--Biography.
Mendel, Hersh, 1893-1968.