I am doing research on Lujo Brentano and I need some info about the relation between Lujo and Karl Marx. "Lujo Brentano was the nephew of the writers Clemens Brentano and Bettina von Arnim, two major figures in the romantic movement in German literature, and the brother of Franz Brentano, a philosopher whose students included Edmund Husserl, Alexius Meinong and Sigmund Freud, among others".
https://en.wikipedia.org/wiki/Lujo_Brentano