Columbia subject headings:
Chemists--Correspondence.
Liebig, Justus, Freiherr von, 1803-1873--Correspondence.
Mulder, G. J. (Gerrit Jan), 1802-1880--Correspondence.
Harvard subject headings:
Princeton subject headings:
Chemists--Netherlands--Correspondence.
Liebig, Justus, Freiherr von, 1803-1873--Correspondence.
Mulder, G. J. (Gerrit Jan), 1802-1880--Correspondence.
Proteins--Analysis.