Lex et libertas : Freedom and Law according to St. Thomas Aquinas. Proceedings of the fourth Symposium on St. Thomas Aquinas' philosophy. Rolduc, november 8 and 9, 1986 - Hedwig, Klaus. (OLS)http://ftis/name/61981; Elders, Léon. (OLS)http://ftis/name/61847 (Libreria Editrice Vaticana, Pontificia Accademia Romana di S. Tommaso d'Aquino,, 1987)