Columbia subject headings:
Booksellers and bookselling--California--San Francisco.
Cowan, Robert Ernest, 1862-1942.
San Francisco (Calif.)--Biography.
Harvard subject headings:
Booksellers and bookselling--California--San Francisco.
Cowan, Robert Ernest, 1862-1942.
San Francisco (Calif.)--Biography.
Princeton subject headings:
Booksellers and bookselling--California--San Francisco.
San Francisco (Calif.)--Biography.