Columbia subject headings:
Immunization--Germany--History--19th century.
Immunization--Germany--History--20th century.
Harvard subject headings:
Immunization--Germany--History--19th century.
Immunization--Germany--History--20th century.
Medical policy--Germany--History--19th century.
Medical policy--Germany--History--20th century.
Princeton subject headings:
Immunization--Germany--History--19th century.
Immunization--Germany--History--20th century.