Columbia subject headings:
Harvard subject headings:
Merkel, Gustav, 1827-1885--Thematic catalogs.
Merkel, Gustav, 1827-1885.
Merkel, Gustav, 1827-1885. Organ music.
Princeton subject headings:
Merkel, Gustav, 1827-1885--Thematic catalogs.
Merkel, Gustav, 1827-1885.
Merkel, Gustav, 1827-1885. Organ music.