cited works:
Quanta Cura
Dignitatis Humanae
MYSTICI CORPORIS CHRISTI
IMMORTALE DEI
Protection of the Jews
SUMMA THEOLOGICA: The various kinds of law (Prima Secundae Partis, Q. 91)
Official Relatio from Dignitatis Humanae
Christmas Address of His Holiness Benedict XVI to the Roman Curia
AU MILIEU DES SOLLICITUDES
Ci Riesce
Sublimus Dei
Newman Reader - Letter to the Duke of Norfolk - Section 6

further reading:

Thomas Pink: What is the Catholic Doctrine on Religious Liberty?

Cardinal Newman on the Syllabus of Errors
Newman Reader - Letter to the Duke of Norfolk - Section 7

Bishop Von Ketteler on Religious Freedom
Opuscula: Religious Freedom (Part I)
Opuscula: Religious Freedom (Part II)
Opuscula: Religious Freedom (Part III)
Opuscula: Religious Freedom (Part IV)

Bishop Dupanloup on the Syllabus, etc.
Opuscula: The Intervention of Mgr. Dupanloup (Part I)
Opuscula: The Intervention of Mgr. Dupanloup (Part II)
Opuscula: The Intervention of Mgr. Dupanloup (Part III)