Columbia subject headings:
Authors, German--18th century--Correspondence.
Merck, Johann Heinrich, 1741-1791--Correspondence.
Harvard subject headings:
Authors, German--18th century--Correspondence
Merck, Johann Heinrich, 1741-1791--Bibliography.
Merck, Johann Heinrich, 1741-1791--Correspondence.
Princeton subject headings:
Merck, Johann Heinrich, 1741-1791--Correspondence.