Columbia subject headings:
May, Karl, 1842-1912--Criticism and interpretation.
Harvard subject headings:
May, Karl, 1842-1912--Criticism and interpretation.
Princeton subject headings:
May, Karl, 1842-1912--Criticism and interpretation.
May, Karl, 1842-1912. Am Rio de la Plata.
May, Karl, 1842-1912. In den Kordilleren.