Related Clues:

• Name that's an anagram of 'lark'
• 'Das Kapital' author Marx
• Capitalism critic Marx
• Marxism's Marx
• Urban of "The Boys"
• Philosopher Marx
• __ 21 down, author of Capital
• Mathematician Weierstrass dubbed the 'father of modern analysis'
• With 33-Down, co-author of "The Communist Manifesto"