Columbia subject headings:
Harvard subject headings:
Baer, Karl Ernst von, 1792-1876--Correspondence.
Botanists--Correspondence.
Naturalists--Correspondence.
Nees von Esenbeck, C. G. (Christian Gottfried), 1776-1858--Correspondence.
Nees von Esenbeck, Elisabeth, 1783-1857--Correspondence.
Princeton subject headings:
Baer, Karl Ernst von, 1792-1876.
Botanists--Correspondence.
Botany--Correspondence.
Nees von Esenbeck, C. G. (Christian Gottfried), 1776-1858.
Nees von Esenbeck, Elisabeth.