Lex et libertas : freedom and law according to St. Thomas Aquinas ; proceedings of the 4. Symposium on St. Thomas Aquinas' Philosophy, Rolduc, November 8 u. 9, 1986 / J. A. Aertsen ... Ed. by L. J. Elders ... Citta del Vaticano : Libreria Ed. Vaticana, 1987