Columbia subject headings:
Harvard subject headings:
Bell, Alexander Graham, 1847-1922--Marriage.
Bell, Mabel Gardiner Hubbard, 1859-1923.
Inventors--United States--Biography
Princeton subject headings:
Bell, Alexander Graham, 1847-1922--Marriage.
Bell, Mabel Gardiner Hubbard, 1857-1923.
Inventors--United States--Biography.