Columbia subject headings:
Knowledge, Theory of.
Popper, Karl R. (Karl Raimund), 1902-1994.
Harvard subject headings:
Knowledge, Theory of.
Popper, Karl R. (Karl Raimund), 1902-1994--Knowledge, Theory of.
Princeton subject headings:
Knowledge, Theory of.
Popper, Karl Raimund, Sir, 1902---Knowledge, Theory of.