Columbia subject headings:
Authors, German--19th century--Biography.
May, Karl, 1842-1912.
Harvard subject headings:
Authors, German--19th century--Biography
Authors, German--20th century--Biography
May, Karl, 1842-1912
Princeton subject headings:
Authors, German--Biography.
May, Karl, 1842-1912--Influence.
May, Karl, 1842-1912.