Columbia subject headings:
Chemistry--History.
Chemists--Germany--Correspondence.
Curtius, Theodor, 1857-1928--Correspondence.
Duisberg, Carl, 1861-1935--Correspondence.
Harvard subject headings:
Chemistry--History
Chemists--Germany--Correspondence.
Curtius, Theodor, 1857-1928--Correspondence.
Duisberg, Carl, 1861-1935--Correspondence.
Princeton subject headings:
Chemistry--History.
Chemists--Germany--Correspondence.
Curtius, Theodor, 1857-1928.
Duisberg, Carl, 1861-1935.