Columbia subject headings:
Heil, Philipp Gottlieb, 1793-1847.
Organ (Musical instrument)--Construction--Germany--Bad Ems.
Organ (Musical instrument)--Germany--Rhineland.
Schöler, Christian Ernst, 1756-1832.
Schöler, Johann Wilhelm, 1723-1793.
Harvard subject headings:
Heil, Philipp Gottlieb, 1793-1847.
Organ (Musical instrument)--Germany--Rhineland.
Organ builders--Germany--Bad Ems.
Schöler, Christian Ernst, 1756-1832.
Schöler, Johann Wilhelm, 1723-1793.
Princeton subject headings: