Columbia subject headings:
Harvard subject headings:
Chemical industry--Germany--History.
E. Merck (Firm)--History.
Merck KGaA--History.
Pharmaceutical industry--Germany--History.
Pharmacy--History
Princeton subject headings:
Chemical industry--Germany--History.
E. Merck (Firm)--History.
Merck KGaA--History.
Pharmaceutical industry--Germany--History.
Pharmacy--History.