1. Hett, W. S. (1935). On the Soul. Parva Naturalia. On Breath, William Heinemann Ltd.
2. Brentano, Franz (1973). Psychology from an Empirical Standpoint, Routledge. First published 1874.
3. Foster, J. R. (1984). “Be Not Afraid!” Pope John Paul II Speaks Out on His Life, His Beliefs, and His Inspiring Vision for Humanity, St. Martin’s Press.
4. Hildebrand, Dietrich (1985). Serce, Wydawnictwo W drodze.
5. Crosby, John Henry (2007). The Heart. An Analysis of Human and Divine Affectivity, St. Augustine’s Press.