Columbia subject headings:
Harvard subject headings:
Humboldt, Alexander von, 1769-1859
Humboldt, Alexander von, 1769-1859--Influence.
Naturalists--Germany--Biography.
Scientists--Germany--Biography
Princeton subject headings:
Bibliographies.
Humboldt, Alexander von, 1769-1859--Bibliography.
Humboldt, Alexander von, 1769-1859.