Portillo Palma, Fabian. “The Essence As a Remedy Against the Resignation of Theory: Refections on the Concept of Essence in the Early Production of Herbert Marcuse (1928-1942)”. Fragmentos de Filosofía, no. 21 (December 29, 2024). Accessed April 6, 2025. https://revistascientificas.us.es/index.php/fragmentos_filosofia/article/view/26721.