St. Thomas Aquinas
"On the Government of Things in General" STh Ia Q.103
Treatise on Law, STh Ia IIae QQ.90-108
Prudence and Government, STh IIa IIae Q.47 AA.10-12
Regnative Prudence and its Species, STh IIa IIae Q.50
Treatise on Justice, STh IIa IIae QQ.57-122
Commentary on Aristotle's Politics
Commentary on Aristotle's Ethics
On Kingship, to the King of Cyprus

Nicomachean Ethics

Pope Boniface VIII
Unam Sanctam – On the Two Swords

Pope Pius IX
Quanta Cura – Condemning Current Errors

Pope Leo XIII
Aeterni Patris – On the Restoration of Catholic Philosophy
Arcanum – On Christian Marriage
Diuturnum – On the Origin of Civil Power
Cum Multa – On Conditions in Spain
Nobilissima Gallorum Gens – On the Religious Question in France
Immortale Dei – On the Christian Constitution of States
Exeunte Iam Anno – On the Right Ordering of Christian Life
Rerum Novarum – On Capital and Labor
Sapientiae Christianae – On Christians as Citizens
Au Milieu des Sollicitudes – On Church and State in France
Tametsi Futura Prospicientibus – On Jesus Christ the Redeemer

Pope St. Pius X
Notre Charge Apostolique – On the Apostolic Mandate
Iucunda Sane – On Pope St. Gregory the Great
Vehementer Nos – On the French Law Separating Church and State
Pascendi Dominici Gregis – On the Doctrines of the Modernists
Communium Rerum – On St. Anselm of Aosta
Edite Saepe – On St. Charles Borromeo

Pope Benedict XV
Ad Beatissimi Apostolorum – Appealing for Peace (1 Nov 1914)

Pope Pius XI
Ubi Arcano Dei Consilio – On the Peace of Christ in Christ's Kingdom
Casti Connubii – On Christian Marriage
Quas Primas – On the Feast of Christ the King
Quadragesimo Anno – On the Reconstruction of the Social Order
Caritate Christi Compulsi – On the Sacred Heart

Pope Pius XII

Pope St. John XXIII

Pope Paul VI

Charles De Koninck
On the Primacy of the Common Good